STATEMENT OF INVENTION:
The present invention discloses a remotely controlled mobile robotic manipulator. This
robot has an articulated manipulator/arm mounted on a four-wheeled mobile base having
articulated suspension. This robot is designed for pick and place application and also be
easily reconfigured to do other tasks.
BACKGROUND OF INVENTION:
Field of invention
The present invention relates to the field of remotely controlled mobile robots having
articulated manipulator which could be reconfigured.
Background of invention
The requirement graph for industrial robots has always been an upward one. Faster robots
with multiple functions to increase productivity and reduce loses are the necessity of the
day. Remotely controlled mobile robots are one such category of robots that is gaining
high popularity. Unlike the controlled environment of the laboratory these mobile
manipulator robots have to endure through challenging environment. These necessitate
the robot to have better designs with tougher and stronger manufacturing techniques and
components. Military, fire department, space research organization, medical etc. are few
sectors where these robots find extensive use. These challenges are considered while
designing and building the prototype under scrutiny.
The current invention envisages one such mobile robot with a 5 axis articulated arm for
pick and place application which could also be easily reconfigured to do other tasks. The
manipulator is built with its driving force fitted at the bottom to distribute the load
effectively for easy handling. The mobile platform employs a novel suspension system
which helps in distributing the load equally to all wheels regardless of the wheels position
giving the mobile platform better control and stability.
Prior Art
• U.S. Pat. No. 8176808 B2 to inventors Fisk et al. discloses a robotic arm with
mobile robot mainly useful for defense sector.
• U.S. Pat. No. 6113343 to inventors Goldenberg et al. discloses a robot designed
for hazardous environments and for explosives disposal. Their wheeled platform
was carrying a winder mechanism for avoiding the foul of remote control cable
with the robot.
• U.S. Pat. No. 4492510 to inventors Tanii et al. discloses a mechanism that drives
a robotic arm with the help of a motor coupled with a pair of planetary gears
assemblies.

• U.S. Pat. No. 3313555 to inventor Reimer presents a novel suspension system
well suited for tractors and other construction vehicles that usually travel over
uneven and rough surface.
• U.S. Pat. No. 5413454 to inventor Movsesian's invention relates to a mobile
robotics arm for a domestic dwelling to handle objects at varying heights like low,
intermediate and high.
• U.S. Pat. No. 4621562 to inventors Carr et al. discloses a remotely controlled
robot with an articulated arm attached to it.
• U.S. Pat. No. 3273912 to inventors Crockett et al. discloses an invention related to
suspensions for off-road vehicles. This suspension system helps in eliminating the
extreme sideways rocking motion of the cab and the load by providing an
alternate pivotal movement for the supporting axels of the front and the rear
wheel about a longitudinal axis of the vehicle.
• U.S. Pat. No. 4840394 to inventor Bickler discloses a suspension system for a
vehicle which maintains a constant weight and traction on all wheels in spite of
one wheel moving considerably higher or lower than the other.
• U.S. Pat. No. 5222409 to inventor Dalakian discloses an articulated arm which
works on an unique link mechanism.
• U.S. Pat. No. 4065001 to inventor Ohnaka discloses a manipulator with includes a
first arm assembly having a base end portion and a free end portion having a
chain and sprocket mechanism to drive it.
• U.S. Pat. No. 6731091 B2 to inventors Hietmann et al. discloses a sophisticated
robotic arm used in industries to automate process. These arms can handle heavy
loads.
• U.S. Pat. No. 6408710 Bl to inventors Kullborg et al. discloses an industrial
articulated robotic arm with gear mechanism which can be used to lift heavy
loads.
• U.S. Pat. No. 4456293 to inventor Panissidi presents a gripper consisting of a four
bar linkage arrangement which helps the gripper fingers to apply a constant
gripping pressure on an object irrespective of the extent to which it is open by
simultaneously moving the two fingers in a parallel manner and in a rectilinearly
aligned path.
• U.S. Pat. No. 3952880 to inventors Hill et al. discloses a gripper for a manipulator
with a pair of jaws relatively pivoted to move between open and close position
when powered by an electric motor.

OBJECT OF THE INVENTION:
The object of this invention was to provide a mobile remotely controlled robot
comprising of an efficient manipulator, which could be operated to do pick and place
application or any other task of choice by reconfiguring the whole manipulator or just its
head.
SUMMARY OF INVENTION:
The invention comprises of two parts, the robotic manipulator or robotic arm which is
fixed on to the mobile platform and is programmed using Arduino®, the AVR based
microcontroller.
A robotic manipulator is basically a chain of rigid bodies called links interconnected to
one another by joints. The chain of links has an end-effector attached to it on one end and
the other end is fixed to the base. The objective of the manipulator is to handle objects by
controlling both the position and orientation of the end-effector.
This invention comprises of a five-axis articulated robotic manipulator with tool pitch
and roll motions having electrically driven DC motors for joint actuation. The physical
structure of the manipulator is such that the base motor is fixed vertically and the motors
for the motion of the shoulder joint, elbow joint and tool pitch fixed horizontally onto the
body and this body is then fixed on to a base motor. Also, the end effector's roll motion
and the gripper mechanism are separately powered by smaller drives mounted at the end
effector itself. These joints are actuated through chain and sprocket mechanism. This
enables the quick replacement of the end effector whenever necessary. Similarly, the
whole manipulator also could be easily detached from the body. Thus, the same robot can
execute multiple tasks.
The current invention incorporated a four-wheeled mobile robot with all wheels fixed and
non-steerable. Each wheel is powered individually and works on the principle of skid
steer. These designs employ unique suspension system that enables them to traverse
irregular surface. This suspension system distribute the load on the mobile platform
relatively equally to all wheels and also reduces the lateral tilting of the robot onto a
wheel going over uneven surface.

Brief Description of the Drawings:
The figures above illustrate various views of the mobile robotic manipulator.
Fig. 1 is the isometric view
Fig.2 is the right side view
Fig. 3 is the top view
Fig.4 is the front view
Fig. 5 is the rear view
PART LIST
Number Parts
1 Base of the manipulator
2 Body of the manipulator
3 Link 1 of the manipulator
4 Link 2 of the manipulator
5 Camera with transmitter
6 Servo motors of the gripper
7 Wrist Joint
8 Elbow Joint
9 Shoulder Joint
10 Infra-red Sensors
11 Rocking Frame
12 Central Axel
13 Tactical Switch/Bump Switch
14 DC Motor
15 Gripper
16 Position of the control unit
17 Batteries
18 Ultrasonic Sensors
19 Chain & Sprocket Mechanism
20 Cross Beam
21 Connecting Rod
DETAILED DESCRIPTION
The objective of developing this remotely controlled mobile robotic manipulator is for
handling materials weighing between 500 - 1000gms. Presently built for pick and place
application, it could be reconfigured without difficulty to do other jobs too.
DC motors fixed at the body power the manipulator. This distributes the weight
effectively and also helps in reducing the load on motors considerably unlike in designs
with the motor fixed at the joints. The body is fixed on to a vertically placed motor at the

base. In between the body and the end effector there are two links, joints at the shoulder
and the elbow interconnect these links. These links are actuated through chain and
sprocket mechanism. The end effector's pitch motion is also controlled by a drive at the
body. Two separate servomotors fixed on the end-effector actuate its roll motion and the
gripping mechanism. This enables the quick replacement of the end effector as a whole
whenever necessary, making the robot a more versatile one. Similarly, the whole
manipulator also could be easily detached from the body.
The basic dimensions are as follows: the shoulder joint is 95mm from the base. The two
links in between the end-effector and the body is 170mm each. The length of the end-
effector from the joint to the tip of the gripper is 135mm.
The rotational limitation of each link is as follows: the shoulder joint "link 1" can rotate
a total of 120 degrees back and forth. Similarly "link 2" can rotate a total of 220 degrees
back and forth and the end-effector can rotate 180 degrees about its joint. The body
attached to the vertically mounted motor rotates the manipulator perpendicularly through
an angle of 340 degrees.
The mobile platform has four fixed wheels powered by four high torque DC motors and
works on the principle of skid-steer. A novel suspension system facilitates the mobile
robot to travel over uneven or rough terrain. This suspension system assists the robot to
distribute the loads equally to all wheels to a greater extent by providing the wheels a
relative vertical movement. Also, the lateral tilting of the robot onto a wheel while going
over uneven surface can be reduced substantially. Unlike in common four-wheeled
vehicle this mobile base has only one axel. This axel is centrally located and has two
rocking frames at either end of it. The front and back wheel on one side of the mobile
base is fixed on to one rocking frame. A cross beam is connected to the two rocking
frames with help of two connecting rods, thus limiting the motion of the frames. Thus
these frames give the wheels the relative vertical movement about the central axel.
The basic dimension of the mobile platform is as follows: the wheel base of the platform
is 500mm and the track width is 420mm. Four 110mm diameter wheels are used in this
model. The approximate height of the platform from the ground level is 175mm.
The specifications of the mobile robot and the robotic manipulator are as follows:
Mobile Platform Specification
Configuration 4 fixed wheel
All wheels independently powered and controlled
Drives Four PMDC servo motors with integral gearboxes and optical
encoders
Controller Arduino®, the AVR based microcontroller
Payload 7-8kgs

Example 1
When the mobile platform runs for 10seconds forward and backward, there is an error of
2.36% from one cycle to the other cycle. Similarly, the body has an error of 5% between
each cycle of rotation from left - right through +/-600, when the shoulder is rotated
through +/-1000 there is an error of 3.8% between each cycle, when the elbow is rotated
through +/-1200 there is an error of 4.17% between each cycle, when the wrist is rotated
through +/-900 there is an error of 4.44% between each cycle, also the end-effector roll
has an error of 5% between each +/-1000 cycle and the gripper opening has an error of
3.2%.
Example 2
The speed of the mobile robot when traversing inclinations of varying degrees are as
follows: on flat ground 0.18m/s, on a 10° inclined plane 0.175m/s, on a 20° inclined plane
0.135m/s, on a 25° inclined plane 0.12m/s, on a 30° inclined plane 0.108m/s, on a 35°
inclined plane 0.06m/s with slippage. At the max Mantis can climb a slop of 37.5°.
Example 3
With its own self weight of 17kgs Mantis can travel at maximum speed of 0.18m/s on flat
ground. As the weight increase the speed decrease: for a weight of 21.4kgs Mantis can
travel at 0.176m/s, for 25.8kgs a speed of 0.172m/s and for 28kgs it has a speed of
0.169m/s.

CLAIMS
We claim:
1. A remotely controlled mobile robot with an articulated robotic manipulator to do
pick and place application or any other task of choice by reconfiguring the whole
manipulator or just its head, the sensory-based robot is called Mantis having two
basic parts namely: a mobile platform with a top speed of 0.18m/s and a robotic
manipulator/arm with a payload capacity of 1000gms.
2. According to the claim 1, the mobile platform has four regular wheels attached to
four fixed motors and is maneuvered using skid steer principle.
3. According to claim 1, a novel suspension system is incorporated into the mobile
platform where two centrally pivoted rocker frames give the wheels a relative
vertical movement and helps in distributing the load relatively equally to all the
wheels even when they are not in the same plane.
4. According to claim 1, the Mantis has a 5 axes articulated robotic manipulator/arm
with a gripper as the end-effector, the links are powered by 4 DC motors with the
help of sprocket and chain mechanism.
5. According to claim 1, a gripper is integrated as the end-effector having a payload
capacity of 1000gms for the Mantis, the gripper's roll motion and opening and
closing is controlled by 2 servo motors.
6. According to claim 1, the end-effector can be easily replaced or reconfigured to
execute multiple tasks and also the manipulator as a whole can be easily detached
from the mobile platform for fitting other tools for customized applications.
7. According to claim 1, the control system incorporated in this invention is an
Arduino® board which integrates an ATmega2560 microcontroller, this is
coupled with a note-book (PC) making the programming easier.
8. According to claim 1, the various sensors incorporated in Mantis are ultrasound
and infrared sensors to map the surroundings, touch sensors to sense collision or
touch and camera to see and record the path of the robot and also assist in the end
effectors job.

ABSTRACT

The present invention relates to the field of remotely controlled mobile robots having
articulated manipulator, which could be reconfigured. The invention basically comprises
of two parts, the 5 axes articulated robotic manipulator or robotic arm, which is fixed on
to a four-fixed wheel mobile platform with skid steering. This remotely controlled mobile
robotic manipulator can handle materials weighing between 500 - 1000gms. Presently
built for pick and place application, this mobile manipulator could be reconfigured
without difficulty to do other jobs too. Since the end-effector can be easily detached from
the arm and also the whole manipulator can be detached from the mobile platform,
multiple tasks like drilling, welding, vacuuming, inspections etc. can be executed with
Mantis.
Mantis finds a wide range of applications, for example it can be used for pick and place
task in hospitals, supermarkets, libraries, laboratories, warehouses and also can be used
for military operations, space researches etc.