DESC:FIELD OF THE INVENTION
The present invention relates to the field of mobility aids and assistive technology more particularly, the present invention pertains to a six-wheeled wheelchair incorporating a torsion bar suspension system, linear actuators, rubber track mechanisms, and smart sensors for autonomous navigation and real-time adjustment of the wheelchair's orientation.

BACKGROUND OF THE INVENTION
Currently, there are three main types of research on electric stair-climbing wheelchairs, both domestically and internationally: crawler-type, wheel-based, and walking-type. Among these, the crawler-type electric stair-climbing wheelchair is heavy, lacks sufficient flexibility for movement, and exerts significant pressure on the edges of stairs during ascension, potentially causing damage. Additionally, it faces considerable resistance when used on flat surfaces and is difficult to maneuver in turns. These issues limit its widespread adoption and use in daily life. The wheel-based electric stair-climbing wheelchair offers greater mobility and flexibility but suffers from lower stability while ascending or descending stairs, with significant fluctuations in the center of gravity, which can cause discomfort for the user. Furthermore, the wheel-based system is bulky and difficult to use on typical residential staircases. The walking-type electric stair-climbing wheelchair moves smoothly and can navigate stairs of varying sizes; however, it requires complex control and is challenging to operate. On flat ground, its range of motion is limited, and its movements are slow. Overall, most of these systems are structurally complex and costly to produce.

In such circumstances, the user faces a real risk of injury, not only from the wheelchair potentially toppling, but also from falling or being subjected to a dangerous, uncontrollable descent. Even in cases where the wheelchair doesn't immediately flip or tumble, the lack of proper stabilization and adjustment mechanisms leaves the user vulnerable to a fall or an unsafe landing. This lack of stability and rapid re-adjustment can undermine the wheelchair's purpose of providing safer, more independent mobility.

The patent application CN202051917U presents a wheelchair with stair-climbing functionality, which belongs to the technical field of mobility aids for disabled individuals. It addresses the technical shortcomings of conventional crawler-type wheelchairs, particularly their less safety performance. However, the described wheelchair design includes mechanical complexity, maintenance challenges, and potential instability during stair climbing, and concerns related to weight and cost. To improve reliability, durability, and user-friendliness, the design may need to be simplified or optimized.

The patent application CN204092378U discloses a wheelchair capable of climbing stairs, comprising a wheelchair frame and running gear located at the bottom of the wheelchair frame. The running gear is characterized by including casters and a first motor that provides driving force to the casters. The wheelchair is equipped with at least four casters, each consisting of a wheel rim, multiple cams positioned within the wheel rim, and push rods that move linearly when engaged by the cams. The second motor provides driving force to the cams. The sidewall of the wheel rim is equipped with pilot holes through which each push rod passes.

The patent application CN111547145A discloses a multi-mode driving crawler-type electric carrying device and its operation control and sharing management method. This device is designed to facilitate the safe and stable transportation of individuals, heavy objects, or ordinary wheelchairs up and down stairs. It features a crawler-type drive system, which allows it to navigate staircases with a slope angle of less than 45 degrees, including those in ancient buildings and non-elevator residential buildings with corridor stairs.

The present invention aims to solve the issues of jerks and uneven movement in traditional wheelchairs by implementing a six-wheeled design with a torsion bar suspension system (200). Further, the use of IoT technology and smart control mechanisms ensures that the wheelchair operates efficiently, providing a user-friendly, smooth, and stable ride.

SUMMARY OF THE INVENTION
The main object of the invention is to provide a six-wheeled IoT-based wheelchair featuring a pair of rubber tracks, each connected to a respective drive sprocket (400) and running along the circumference of the wheels on either side of a frame structure. The wheelchair includes a torsion bar suspension system (200) connected to a pair of wheels (800) on each side of the frame structure, with a chassis (100) having a first and second side. One end of each torsion bar (201) is fixed to the chassis (100).

Another object of the invention is to provide the suspension system (200) includes multiple torsion bars (201), each having one end fixed to the chassis (100) and the other end fixed to a torsion arm (202), which is oriented perpendicularly to the torsion bar (201). A spindle (203) is attached to each torsion arm, supporting a wheel of the wheelchair. The torsion bars (201) are arranged in at least three sets, with each set comprising two torsion bars (201) positioned closely together, located on each side of the chassis (100). The spindles (203) of the torsion arms (202) are positioned at opposite ends of the chassis (100) to support the wheelchair wheels.

Another object of the invention is to configure each torsion bar (201) to generate and store torsional forces when a wheel encounters an obstacle or uneven terrain. These forces are then released to return the wheel to its original position once the obstacle is cleared. The suspension system (200) is designed to isolate vertical motion or jerks caused by terrain irregularities, minimizing the transmission of disturbances to the chassis (100) and ensuring a smoother, more comfortable ride for the wheelchair user.
Another embodiment of the present invention provides for one end of the torsion bar (201) to be fixed to the chassis (100) of the wheelchair. The opposite end of the torsion bar (201) is connected to a torsion arm (, which is oriented perpendicular to the axis of the bar. The torsion arm is rigidly attached to a spindle (203), with the spindle (203) functioning to support the respective wheel of the wheelchair. The configuration allows for effective torsional resistance and rotational movement of the wheel, contributing to enhanced stability and maneuverability of the wheelchair.
Another embodiment of the present invention provides that when the wheelchair is positioned on a substantially horizontal surface, the wheels are aligned in a horizontal orientation relative to the surface. The alignment ensures that the wheels remain level and stable, thereby optimizing the balance and functionality of the wheelchair when in use on flat terrain.
Another object of the present invention is to provide a mechanism whereby, when the wheelchair transitions over a vertical obstacle, the linear actuator (500) maintains the horizontal orientation of the seat relative to the ground. Simultaneously, the track mechanism facilitates smooth movement over the obstacle, enabling the wheelchair to effectively traverse uneven terrain or vertical obstacles. The configuration ensures that the seat remains level and stable, while the track system provides the necessary support and traction for efficient navigation over challenging surfaces.
Yet another object of the invention is to provide the torsion bar is fixed at one end to the chassis (100), while the other end is connected to a torsion arm perpendicular to the bar. The torsion arm is linked to a spindle (203) where the ground wheels are attached. The suspension system (200) allows the wheels to respond dynamically to terrain changes, ensuring that the wheelchair maintains optimal contact with the ground at all times.
Another object of the invention is to provide a wheelchair design includes idler wheels, which are elevated above the ground. The idler wheels support the track and ensure that the rubber track moves smoothly around the drive sprockets (400) without causing excessive wear or strain on the system.
Yet another object of the invention is to provide the suspension system (200) is designed to isolate vertical motion or jerks experienced by the wheels, resulting from interaction with terrain irregularities, from the chassis (100), thereby minimizing the transmission of disturbances to the mounted load or seat.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1: Illustrates a side view of the six-wheeled IoT-based wheelchair.
Figure 2: Illustrates isometric view of a six-wheel wheelchair.
Figure 3: Illustrates the 3D view of the six-wheeled IoT-based wheelchair.
Figure 4: Illustrates the front view of the idler wheel (700).
Figure 5: Illustrates the the perspective view of the prototype in operation across various terrain types.
Figure 6: Illustrates a 3D representation of the six-wheeled IoT-based wheelchair.
Figure 7: Illustrates the front view of the idler wheel (700), showing the central hub (701) connected to the rubber track (300) and mounted on the chassis (100).
Figure 8: Illustrates the Torsion Bar Suspension Assembly (200).
Figure 9: Illustrates the positioning of the ultrasonic sensor.
Figure 10: illustrates the integration of Infrared (IR) sensors to detect approaching staircases.

DETAILED DESCRIPTION OF THE INVENTION
For the purpose of promoting, an understanding of the principles of the invention, references will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

Reference herein to “one embodiment” or “another embodiment” means that a particular feature, structure, or characteristics described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in a specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, the diagrams representing one or more embodiments of the invention do not inherently indicate any particular order nor imply any limitations in the invention.

The present invention pertains to a six-wheeled, IoT-enabled wheelchair equipped with a torsion bar suspension system (200) and rubber tracks (300). The wheelchair includes a torsion bar suspension system (200) connected to a pair of wheels on each side of the frame structure, with a chassis (100) having a first and second side. One end of each torsion bar is fixed to the chassis (100). The suspension system (200) includes multiple torsion bars (201), each having one end fixed to the chassis (100) and the other end fixed to a torsion arm (202), which is oriented perpendicularly to the torsion bar. The spindle (203) is attached to each torsion arm (202), supporting a wheel of the wheelchair. The torsion bars (201) are arranged in at least three sets, with each set comprising two torsion bars (201) positioned closely together, located on each side of the chassis (100). The spindles (203) of the torsion arms (202) are positioned at opposite ends of the chassis (100) to support the wheelchair wheels.

A preferred embodiment of the present invention comprises a pair of rubber tracks (101), each linked to a respective drive sprocket (400) and running along the circumference of the wheels on both sides of the wheelchair's frame structure. The design further incorporates at least one torsion bar suspension system (200), which is connected to a pair of wheels (800) on each side of the frame. One end of the torsion bar (201) is securely fixed to the chassis (100) of the wheelchair, while the opposite end is coupled to a torsion arm (202) that is oriented perpendicular to the bar. The torsion arm (202) is attached to a spindle (203), which in turn supports the respective wheel of the wheelchair. During operation, when the wheelchair is positioned on a substantially horizontal surface, the wheels remain aligned horizontally relative to the surface. When the wheelchair encounters a vertical obstacle, a linear actuator ensures the horizontal orientation of the seat relative to the ground is maintained. Simultaneously, the track mechanism enables smooth and effective movement over the obstacle, allowing the wheelchair to transition seamlessly across uneven terrain or vertical barriers.

Another embodiment of the present invention includes rubber tracks (300) that further comprise treads and inward-facing spikes, which are designed to provide enhanced grip, thereby preventing skidding or slipping of the wheels, idler wheels (700), or drive sprockets (400) during traversal of obstacles. The treads are positioned to maximize surface contact and traction, while the inward-facing spikes effectively engage the terrain, improving the stability and maneuverability of the wheelchair in challenging or uneven environments. The configuration ensures reliable performance and prevents undesirable wheel slippage, enhancing the overall efficiency of the wheelchair during operation over varied surfaces.

An embodiment of the present invention provides the chassis (100) consisting of a first and a second side. One end of each torsion bar (201) is fixed to the chassis (100), while the opposite end is secured to a torsion arm (202). The torsion arms (202) are oriented perpendicularly to their respective torsion bars (201), and spindles (203) are mounted on each torsion arm (202). These spindles (203) are configured to support the wheels of the wheelchair. Another embodiment of the present invention involves a wheelchair chassis (100) incorporating a dual-layer structure. The outer frame is designed to absorb external impacts, while the inner reinforcement grid efficiently redistributes the user's weight during dynamic movements, such as climbing stairs or navigating uneven terrain. The construction enhances both the durability and comfort of the wheelchair, improving its performance across various surfaces.

A preferred embodiment of the present invention provides a torsion bar suspension system (200), which is characterized by a plurality of torsion bars (201), each having one end fixed to the chassis (100) and the other end fixed to a torsion arm (202), with the torsion arm (202) oriented perpendicularly to the respective torsion bar (201). A spindle (203) is attached to each torsion arm (202), wherein the spindle (203) is adapted to support a wheel of the wheelchair. The torsion bars (201) are arranged in at least three sets, with each set comprising two torsion bars (201) positioned in close proximity. One set is located on each side of the chassis (100), and the spindles (203) of the torsion arms (202) are positioned at opposite ends of the chassis (100) to support the wheels of the wheelchair. Each torsion bar (201) is configured to generate and store torsional forces when a wheel traverses an obstacle or uneven terrain, releasing these forces to return the wheel to its original position once the obstacle has been cleared. The suspension system (200) is specifically designed to isolate vertical motion or jerks experienced by the wheels due to interaction with terrain irregularities, minimizing the transmission of such disturbances to the chassis (100) and, consequently, to the mounted load or seat.

Another embodiment of the present invention is to provide the wheelchair comprising a frame structure that supports the chair. The chair is mounted on a base structure, which is integrated with a linear actuator attached to the base of the chair. The linear actuator (500) is designed to control the angular displacement of the seat, ensuring that the chair maintains horizontal alignment with respect to the ground during various movements, particularly when traversing uneven surfaces or ascending and descending stairs. Another embodiment of the present invention is to provide the rubber tracks (300) are constructed of a flexible material designed to enhance traction and stability when traversing uneven or rugged terrain.

Another embodiment of the present invention incorporates the linear actuator (500) designed to convert linear motion into angular displacement of the seating portion of the wheelchair, thereby maintaining the horizontal orientation of the seat during dynamic transitions, including when ascending or descending stairs. The linear actuator (500) is configured to adjust the angle of the seat, enabling the wheelchair to modify its seating position in response to varying terrain conditions. In this embodiment, the linear actuator (500) is configured to regulate the pitch of the chair, ensuring that the seat remains level relative to the ground as the wheelchair navigates over obstacles or irregular surfaces. The functionality provides enhanced stability and comfort for the user during transitions over challenging environments.
Another embodiment of the present invention is to provide the wheelchair frame structure incorporates torsion bar suspension (200) elements to provide smooth movement over uneven terrain. When the wheelchair traverses an obstacle or rough surface, the tracks move over it, pushing the wheels upward.
Another embodiment of the present invention includes at least one sensing device integrated to detect obstacles or objects within the wheelchair's path of motion. The sensors play a critical role in ensuring the safety of both the wheelchair and its user by providing real-time environmental data. In this embodiment, the sensing device comprises one or more of the following: a proximity sensor, a camera system, or an ultrasonic sensor. Each of these components is adapted to detect objects in the wheelchair's path, enabling autonomous navigation and facilitating effective obstacle avoidance. The integration of sensing technologies enhances the wheelchair's ability to navigate complex environments while minimizing the risk of collision or other safety hazards.

An embodiment of the present invention is configured that the torsion bar suspension system (200) is designed to isolate vertical forces induced by uneven terrain. The isolation mechanism effectively minimizes the transmission of these vertical forces to both the chassis (100) and the user. As a result, the wheelchair achieves a smoother, more stable ride, particularly when traversing rough, uneven, or irregular terrain surfaces. The suspension system (200) absorbs and dissipates the vertical shocks and vibrations, thereby enhancing comfort and maintaining stability throughout the movement of the wheelchair.

In the preferred embodiment of the present invention, an experimental setup is designed to evaluate the effectiveness of the torsion bar suspension system (200) and rubber track (300) mechanism incorporated in a six-wheeled wheelchair, particularly in minimizing jerks and ensuring a smooth ride over stairs and uneven terrain. The objective of this experimental validation is to assess the improvement in ride quality achieved by the suspension system (200) in comparison to conventional wheelchair designs. In this embodiment of the existing wheelchair model (Control Group) in which the first wheelchair model used in the experimental validation is a conventional wheelchair, representative of the current state-of-the-art, which does not incorporate any suspension mechanism or specialized terrain-adaptive features. This control wheelchair is intended to establish baseline data on the performance of a standard wheelchair when traversing the test conditions.

Another embodiment of the experimental setup the proposed Wheelchair Model (Test Group) in which the second model is the proposed six-wheeled wheelchair, which features a torsion bar suspension system and rubber track mechanism. The model is designed to reduce jerks and vibrations during movement over uneven surfaces, including stairs and rough terrain. The suspension system and rubber tracks are configured to absorb shock, distribute weight evenly, and maintain stability, thereby minimizing the impact forces on the user.

Another embodiment of the experimental setup II. Testing Conditions in which Staircase with 30° a staircase consisting of ten steps, each with a height of approximately 10 cm, is used to simulate a common challenge for wheelchair users, particularly in environments where ramps are unavailable. The incline of the staircase is set at approximately 30°, a typical slope found in many staircases in residential and public spaces. This test condition is intended to evaluate how well the proposed wheelchair model can mitigate the jerking motion when ascending or descending stairs. Another embodiment of the present invention rough Terrain Track in which the model designed rough terrain track is employed to simulate real-world conditions including gravel paths, curbs, and uneven outdoor surfaces. The rough terrain track includes a series of obstacles, bumps, and irregularities that mimic the common challenges faced by wheelchair users in environments that lack smooth, paved surfaces. The track tests the ability of the six-wheeled wheelchair to traverse a variety of terrain types while maintaining user comfort.

In another embodiment of the present invention, a set of advanced measurement tools is incorporated into the wheelchair design to evaluate the performance of its suspension system and overall ride quality. Accelerometers are strategically placed on the wheelchair chassis to quantify the vibrations and jerks experienced during movement. These accelerometers capture critical data regarding the magnitude, frequency, and duration of vibrations, as well as any sudden jerks that occur, particularly when the wheelchair traverses stairs, rough terrain, or encounters various obstacles. The data obtained from these accelerometers are pivotal in comparing the jerk reduction capabilities of the proposed wheelchair model with a control group, providing valuable insights into its overall performance. Furthermore, force sensors are installed on the chassis to measure pressure variations during the tests. These sensors detect changes in the force exerted on the wheelchair as it interacts with different surfaces, including stairs and rough terrain. By monitoring these force measurements, the effectiveness of the wheelchair's suspension system in absorbing shock and minimizing the transfer of force to the user can be assessed. This comprehensive data collection ensures a smoother, more comfortable ride for the user, thereby enhancing the wheelchair’s overall functionality.

Overall the present invention prove that the data on vibration, jerk reduction, and pressure variation are captured and analyzed to assess the efficacy of the torsion bar suspension and rubber track mechanism in enhancing wheelchair performance and user comfort. The results of this validation are expected to demonstrate the potential benefits of the invention in reducing discomfort and increasing mobility for wheelchair users.

In another preferred embodiment of the present invention, the experimental validation of the adaptive speed control mechanism and optimized center of gravity in a six-wheeled wheelchair is carried out through a detailed experimental setup, as outlined below.
In this embodiment of the experimental setup, the wheelchair undergoes testing across multiple scenarios to assess its performance under varying conditions. The first scenario involves Ascending Stairs (30° incline), where the wheelchair is tested while ascending a staircase with a 30° incline. This scenario simulates the challenge of climbing stairs with a dynamic load, requiring the wheelchair to adjust its speed and maintain balance while managing the forces of gravity. The second scenario, Descending Stairs (30° decline), evaluates the wheelchair's performance while descending stairs with a 30° decline. This test simulates the reverse scenario, where the wheelchair must maintain a controlled, slower descent to prevent instability, ensuring that the user remains secure throughout the movement.A third scenario, Flat Terrain Movement, involves testing the wheelchair on a flat surface to evaluate its baseline performance. This scenario focuses on speed control and the wheelchair’s response to normal, stable conditions, providing a reference point for comparison with other test conditions.

Finally, the wheelchair is tested for Navigating a 20 cm High Obstacle. In this scenario, the wheelchair is tasked with overcoming a 20 cm high obstacle. This requires the system to dynamically adapt in real time, adjusting the center of gravity to maintain stability while navigating the uneven terrain.

Another embodiment of the experimental setup 2 in which the Inertial Measurement Unit (IMU) is employed to measure and track the tilt angles of the wheelchair during different test scenarios. By analyzing the tilt data, the system can determine when adjustments are needed to maintain optimal balance, particularly when navigating stairs or obstacles. In this embodiment the speed sensors are used to monitor the acceleration and deceleration of the wheelchair in real-time. The data allows for precise adjustments to be made in the adaptive speed control mechanism, ensuring that the wheelchair’s speed is optimized for the given terrain and incline. Further in this embodiment the force sensors are installed on the wheelchair to measure the stability forces acting on the chassis. The sensors track pressure variations during movement, helping to evaluate the effectiveness of both the adaptive speed control and center of gravity optimization in preventing instability.

In another embodiment of the experimental setup, a comparison is made between an existing wheelchair model and the proposed six-wheeled wheelchair equipped with an adaptive speed control mechanism. The existing wheelchair model, which lacks such a mechanism, maintained a constant speed regardless of the terrain or incline. This limitation led to significant instability, especially when climbing stairs, as the user was required to manually adjust the speed. Such adjustments often resulted in an uncomfortable and unsafe experience. furthermore, descending stairs presented challenges, as the wheelchair failed to slow down, increasing the risk of sudden drops or jerks that could cause discomfort or injury.

In contrast, the proposed six-wheeled wheelchair features an advanced adaptive speed control system that automatically adjusts its speed in response to both the terrain's incline and the user's weight. When ascending stairs, the system increases the speed to counteract gravitational resistance, ensuring a smoother and more efficient climb. Conversely, when descending, the system reduces the speed to enable a controlled, gradual descent, thereby preventing sudden drops that could lead to instability or discomfort. This adaptive speed control enhances both the safety and comfort of the user, particularly when navigating challenging environments such as stairs or uneven terrain.
In this embodiment of the existing wheelchair, with a high and fixed center of gravity, presented a significant risk of toppling, particularly when navigating obstacles or traversing stairs. The wheelchair's design required manual balancing by the user, which added strain and made movement over uneven terrain more difficult and less stable.
In this embodiment the proposed six-wheeled wheelchair featured a dynamically adjustable centre of gravity, achieved through the use of a linear actuator that adjusted the tilt of the chair. The system continuously maintained the wheelchair’s horizontal alignment during all test scenarios. This even distribution of weight prevented tipping, even while navigating stairs or crossing obstacles. The optimized centre of gravity allowed for a more stable and safe experience, significantly reducing the risk of toppling, and easing user maneuverability across challenging surfaces.

Overall, the results from the second embodiment of the experimental setup demonstrate that the proposed six-wheeled wheelchair, with its adaptive speed control mechanism, significantly enhances stability by adjusting the speed according to the terrain conditions. The adjustment improves both user comfort and safety, particularly when navigating challenging environments. Furthermore, the optimization of the wheelchair's centre of gravity, achieved through dynamic tilt adjustments, reduces the risk of toppling during critical movements such as stair traversal or obstacle navigation. These innovations make the wheelchair safer and easier to use in dynamic and unpredictable environments, representing a significant advancement over conventional wheelchair designs.

In accordance with a preferred embodiment of the present invention, the experimental setup for assessing the autonomous terrain navigation and obstacle-handling capabilities of the six-wheeled wheelchair is outlined below. The third experimental setup evaluates the integration of Internet of Things (IoT) components that enable the wheelchair to autonomously navigate various terrains, detect obstacles, and make real-time adjustments in a manner that ensures safety and operational efficiency. In this embodiment, the first test condition involves an indoor environment with a flat surface, where random obstacles such as furniture, low barriers, and other objects are placed at various intervals. The wheelchair is required to autonomously detect these obstacles and adjust its navigation path to avoid collisions, thereby demonstrating the system’s capability to operate effectively in a confined, controlled setting.

The second test condition simulates outdoor terrain, such as grass, gravel, or concrete paths with irregular surfaces. This condition evaluates the wheelchair’s ability to maintain stable movement over uneven ground while dynamically adjusting its speed and direction to accommodate the changes in terrain. The third test condition involves the sudden appearance of an obstacle in the wheelchair’s path, simulating an emergency scenario. In this case, the wheelchair must react in real time, utilizing its sensors to detect the obstacle and initiate an emergency stop or navigational adjustment. This ensures the avoidance of a collision and enhances the user's safety.

In another embodiment of the experimental setup, the wheelchair is equipped with an array of ultrasonic sensors strategically positioned around the chassis (100). These sensors provide continuous feedback by emitting sound waves and measuring the time it takes for the waves to return after hitting an object. The data enables the system to detect obstacles within a specified radius of up to 1 meter, allowing the wheelchair to predict potential collisions and adjust its movement path accordingly. The sensor data is integrated with the wheelchair's control system, providing real-time input for effective obstacle avoidance. Furthermore, an Inertial Measurement Unit (IMU) is installed to monitor the tilt angles and orientation of the wheelchair. The IMU measures changes in pitch, roll, and yaw, feeding this information to the control system. Based on this input, the wheelchair’s tilt is dynamically adjusted to maintain stability when traversing inclines or uneven surfaces, thereby preventing the wheelchair from tilting forward or backward in ways that could destabilize the user.

Moreover, the wheelchair incorporates a PID (Proportional-Integral-Derivative) motor controller, which manages the speed and direction of the wheelchair’s motors. The PID controller is tuned to optimize smooth navigation by minimizing abrupt changes in velocity and direction, ensuring a comfortable ride for the user. It works in conjunction with the ultrasonic sensors and Inertial measurement unit to make real-time adjustments, such as slowing down or changing direction, in response to detected obstacles or changes in terrain.
In this embodiment, the existing wheelchair model, this lacked autonomous navigation capabilities, required manual intervention for obstacle detection and avoidance. When encountering obstacles in its path, the user had to actively steer the wheelchair around objects, as there was no predictive mechanism to detect obstacles ahead of time. This manual process often led to collisions, especially in environments with numerous obstacles.
In contrast, the proposed six-wheeled wheelchair demonstrated a significant improvement in obstacle detection and avoidance. Equipped with ultrasonic sensors, the wheelchair was able to detect obstacles within a 1-meter radius, providing early warnings to the control system. Upon detecting an obstacle, the wheelchair autonomously adjusted its direction and speed to avoid a collision, either by navigating around the obstacle or halting its movement when necessary. This proactive obstacle avoidance system ensured smooth navigation in environments with random obstacles, such as indoor settings and crowded spaces.
Furthermore, the existing wheelchair model exhibited poor stability when navigating inclines and uneven surfaces. When traversing ramps, stairs, or surfaces with irregularities, the wheelchair tended to tilt forward or backward, requiring manual adjustments by the user. These tilt-induced imbalances not only compromised the wheelchair’s stability but also placed additional strain on the user, affecting both safety and comfort.
The proposed six-wheeled wheelchair, however, incorporated an IMU-based control system that dynamically adjusted the wheelchair's tilt in real time to maintain a stable position. This system continuously monitored the tilt angles and made automatic corrections to ensure that the wheelchair remained level, even when traversing uneven terrain or navigating inclines. As a result, the user experienced improved stability, preventing discomfort or the risk of tipping over during movement across varied surfaces.
Overall, the third experimental setup, which involved the experimental validation of the six-wheeled wheelchair’s autonomous terrain navigation and obstacle-handling capabilities, demonstrates a marked improvement over conventional wheelchair models. The integration of ultrasonic sensors, an IMU-based control system, and a PID motor controller enables the wheelchair to autonomously navigate and adapt to its environment. These features work together to detect obstacles, avoid collisions, and maintain stability by dynamically adjusting tilt and speed. As a result, the proposed wheelchair offers a safer, more hands-free experience for users with mobility impairments, particularly in environments with unpredictable obstacles or varying terrain conditions. The system’s ability to autonomously adjust in real time significantly enhances both the comfort and safety of the user, making the six-wheeled wheelchair an advanced mobility solution for individuals with significant physical disabilities.
In a preferred embodiment, Figure 1 illustrates a side view of the six-wheeled IoT-based wheelchair. This embodiment features a pair of rubber tracks (300), each connected to a respective drive sprocket (400), which runs along the circumference of the wheels on either side of the frame structure. The IoT-based system (600) is integrated with the drive sprocket (400). Furthermore, the linear actuator (500) is attached to the base of the chair, with an extension tube (501) and an actuator motor socket (502). The wheelchair also incorporates at the torsion bar suspension system (200), which is coupled to a pair of wheels (800) on each side of the frame structure. The chassis (100) of the wheelchair consists of a first side and a second side, with the torsion bar suspension system (200) fixed to the chassis (100). The torsion bar suspension system (200) is designed to support the wheelchair and absorb impacts from the wheels (800), providing enhanced stability and comfort.
In the preferred embodiment figure 2 illustrates isometric view of a six-wheel wheelchair draft, showcasing a robust, user-centric design aimed at improving wheelchair functionality, stability, and adaptability for a wide range of users and terrains.
In the preferred embodiment, Figure 3 illustrates the side view of the prototype operating on a staircase. The ground wheels (800) move along rubber tracks (300), which are driven by drive sprockets (400) attached to motors on either side. As the drive sprockets (400) rotate, they transfer motion to the rubber tracks (300), enabling movement. The idlers (700), mounted on axles on both sides of the chassis (100), maintain proper tension and alignment of the tracks during operation. Further, the drive sprockets (400) are affixed to the motor shafts using axles, ensuring reliable power transmission.
The exoskeleton, ground wheels (800), idlers (700), and drive sprockets (400) are fabricated from Mild Steel (205) due to its ease of welding and superior durability compared to aluminum. Mild steel provides greater longevity for the wheelchair, making it more suited for long-term use. Although mild steel's increased weight is a trade-off compared to aluminum, the design includes compensatory measures to mitigate this disadvantage, ensuring the overall performance and structural integrity of the system.
In a preferred embodiment, Figure 4 illustrates the perspective view of the prototype in operation across various terrain types. The system is designed to adapt to diverse environments, showcasing its versatility and robust capabilities. Specifically, the prototype demonstrates its ability to navigate an ascending staircase with an incline range between 20°- 30°. This is achieved through the integration of advanced locomotion mechanisms that facilitate stable and efficient traversal, allowing the prototype to ascend stairs with precise coordination of its actuation system. Similarly, the prototype can descend stairs with a 20°-30° decline, utilizing adaptive balance algorithms and feedback systems to ensure safe and controlled movement down the incline.
Further in this embodiment to its stair navigation capabilities, the prototype is also designed to move seamlessly across flat terrain. This flat terrain movement is facilitated by its robust chassis (100) and optimized movement algorithms, ensuring stability and efficiency on level surfaces. Furthermore, the prototype exhibits its ability to navigate obstacles with a height range between 10-20 cm, a crucial feature for environments where uneven surfaces or barriers are prevalent. The system dynamically adjusts its path planning and force distribution to successfully overcome obstacles of this height, ensuring that the prototype can navigate complex environments without losing stability or encountering undue strain on its mechanisms. Collectively, these features enable the prototype to operate in a wide range of real-world settings, demonstrating its versatility, adaptability, and durability in challenging environments.
In a preferred embodiment, Figure 5 illustrates a 3D representation of the six-wheeled IoT-based wheelchair, the arrangement of the wheelchair's wheels (800) positioned within the central hole (801) of each wheel, which are connected to the rubber track (300). The torsion bar suspension system (200) is mounted on either side of the mechanism, ensuring effective load distribution and shock absorption. The embodiment further includes an idler wheel (700) connected to a central hub (701) and an idler wheel grip (702). The configuration ensures superior stability and facilitates jerk-free movement, particularly across stairs and uneven terrains. The track-based structure uniformly distributes the load, minimizing localized stress and preventing sudden impact shocks, thereby enhancing the wheelchair's performance and comfort during operation on challenging surfaces.
In a preferred embodiment, Figure 6 illustrates the front view of the idler wheel (700), showing the central hub (701) connected to the rubber track (300) and mounted on the chassis (100). This configuration ensures that the idler wheel (700) serves as a pivotal component in maintaining the alignment and tension of the rubber track (300), contributing to the efficient operation of the wheelchair. The central hub (701) is securely attached to the chassis (100), facilitating the smooth movement of the track while minimizing wear and tear, and ensuring optimal traction and stability during operation.

In the preferred embodiment, Figure 7 illustrates the Torsion Bar Suspension Assembly (200), which incorporates a torsion bar (200) designed to operate based on the principles of torsion and shear stress, providing effective suspension for the wheelchair. The torsion arm (202) is fixed at both ends, with a spindle (203) attached at the other end to connect the ground wheels (800). When the wheelchair encounters an obstacle or uneven terrain, the track moves over it, causing the wheels to be pushed upward. This upward movement generates torsion in the torsion bar (201). Once the track passes the obstacle, the stored torsion is released, allowing the wheels to return to their original position. The mechanism effectively isolates the wheelchair's base from the impact, ensuring a smooth ride and minimizing any jerks or disturbances that might affect the occupant.

In the preferred embodiment, Figure 8 illustrates the positioning of the ultrasonic sensor, which is integrated into the design to enhance the vehicle's obstacle detection capabilities. The ultrasonic sensor measures the distance between the vehicle and any obstacles in its path by emitting sound waves and calculating the time taken for the waves to return. This data allows the vehicle to assess its proximity to obstacles in real-time. Based on the calculated distances, the vehicle is equipped with the ability to autonomously stop when an obstacle is detected within a predefined range, improving its safety and responsiveness in dynamic environments.

In the preferred embodiment, Figure 9 illustrates the integration of Infrared (IR) sensors to detect approaching staircases. Two IR sensors are strategically placed on either side of the vehicle to ensure proper alignment with the stairs. These sensors continuously monitor the surroundings and provide real-time data to the system. If the vehicle is not correctly aligned with the staircase, the IR sensor data is used to adjust the vehicle's position, realigning it to ensure smooth and accurate staircase navigation. The mechanism enhances the vehicle's ability to autonomously navigate stairs with precision and stability.
,CLAIMS:We claim,
1. A six-wheeled IoT-based wheelchair comprising:
a. a pair of rubber tracks (300), each connected to a respective drive sprocket (400) and running along the circumference of the wheels on either side of a frame structure;
b. at least one sensing device constructed and adapted to detect objects along a direction of motion of said wheelchair;
c. at least one torsion bar suspension system (200), wherein the suspension system (200), is connected to a pair of wheels (800) on each side of the frame structure;
d. a chassis (100) having a first side and a second side, with one end of each torsion bar (201) fixed to the chassis (100);
e. the torsion bar suspension system (200) characterized by:
i. a plurality of torsion bars (201), each torsion bar (201) having one end fixed to the chassis (100) and the other end fixed to a torsion arm (202), the torsion arm (202) being oriented perpendicularly to the respective torsion bar(201);
ii. a spindle (203) attached to each torsion arm (202), wherein the spindle (203) is adapted to support a wheel of the wheelchair (900);
iii. the torsion bars (201) being arranged in at least three sets , each set comprising two torsion bars (201) positioned in close alignment, with one set being located on each side of the chassis (100) and the spindles (203) of the torsion arms (202) positioned at opposite ends of the chassis (100) to support the wheels of the wheelchair (900);
iv. each torsion bar (201) being configured to generate and store torsional forces when a wheel traverses an obstacle or uneven terrain, and to release the torsional forces to return the wheel to its original position once the obstacle has been cleared;
wherein the suspension system (200) is designed to isolate vertical motion or jerks experienced by the wheels, resulting from interaction with terrain irregularities, from the chassis (100), thereby minimizing the transmission of disturbances to the mounted load or seat.

2. The six-wheeled Iot based wheelchair as claimed in claim 1, wherein the rubber tracks further comprise treads and inward-facing spikes to provide grip, preventing skidding or slipping of the wheels, idler wheels (700), or drive sprockets (400) during obstacle traversal.

3. The six-wheeled iot based wheelchair as claimed in claim 1, wherein the idler wheels (700) and ground wheels (800) are designed with holes to accommodate the inward-facing spikes of the rubber tracks (400).
4. The six-wheeled IoT-based wheelchair of claim 1, wherein the torsion bar suspension system (200) is designed to isolate vertical motion or jerks from the chassis (100), minimizing the transmission of disturbances to the chair or mounted load, thereby providing a smooth and stable ride over uneven terrain.

5. The six-wheeled IoT-based wheelchair as described in claim 1, wherein, during use, the wheels remain horizontally aligned with the surface when the wheelchair is on a substantially level plane. Upon encountering a vertical obstacle, the linear actuator (500) keeps the seat oriented horizontally with respect to the ground, while the track mechanism allows for smooth traversal over the obstacle.

6. The six-wheeled IoT-based wheelchair of as claimed in claim 1, wherein the sensing device is configured to provide real-time data regarding potential obstacles or obstructions in the path of the wheelchair, thereby enabling the system to facilitate dynamic navigation, collision avoidance, and enhanced safety features.

7. The six-wheeled IoT-based wheelchair of as claimed in claim 1, wherein the chassis (100) incorporates a dual-layer structure, where the outer frame absorbs external impacts, while the inner reinforcement grid efficiently redistributes the user's weight during dynamic movements, including climbing stairs or navigating uneven terrains.

8. The six-wheeled IoT-based wheelchair of claim 1, wherein the wheel and track assembly is equipped with a quick-detach mechanism. The quick-detach mechanism is designed to facilitate hassle-free maintenance, part replacements, and customization.

9. The six-wheeled IoT-based wheelchair of claim 1, wherein the frame is constructed with materials and design features that provide shock-absorbing properties, which effectively reduce user discomfort during high-impact operations by dampening the effects of external forces, thereby minimizing the transmission of shock and vibrations to the seated user during movement over rough or uneven terrain.

10. A six-wheeled IoT-based wheelchair (600) comprising:
i. an ultrasonic sensor configured to detect obstacles in front of the vehicle and calculate a distance between the vehicle and said obstacles;
ii. a pair of infrared (IR) sensors, each positioned on opposing sides of the vehicle, configured to detect staircases or similar vertical discontinuities in the path ahead, and to provide data indicative of the vehicle's alignment relative to the staircase; and
iii. a control unit that processes the distance data from the ultrasonic sensor to autonomously stop the vehicle and adjusts the vehicle's position using the IR sensor data to ensure proper alignment and safe approach to staircases, thereby enabling the vehicle to navigate obstacles and stairs with minimal user intervention.

11. The six-wheeled IoT-based wheelchair of claim 10, wherein the ultrasonic sensor enables the vehicle to autonomously stop upon detecting the obstacles within a predefined threshold distance.

12. A method of providing stability and comfort to a user of a six-wheeled IoT-based wheelchair comprising the steps of:
a) engaging a torsion bar suspension system (200) to isolate vertical forces transmitted from uneven terrain to the chassis (100);
b) using a linear actuator (300) to adjust the horizontal orientation of the seat with respect to the ground during movement across varying terrain;
c) utilizing the IoT-based control system (600) to optimize suspension and tracking settings based on terrain feedback received from sensors.

Dated this 27th Day of March 2025