FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"ADAPTIVE OBSTACLE DETECTING SYSTEM FOR AUTOMOTIVE
VEHICLES"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C., SATPUR,
NASHIK - 422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION DESCRIBES THE NATURE OF THE INVENTION AND MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF INVENTION
The present invention is related to the obstacle detection system for automotive vehicles. More particularly the present invention is related to the obstacle detection system that assists in reverse parking of an automotive vehicle. This system will have more efficient sensing of the smaller obstacles at all the vehicle heights.
BACKGROUND AND PRIOR ART SEARCH
Normally ultrasonic waves are transmitted to around the vehicle body and based on comparison of the reflected waves from the obstacle with the reference signal, it will determined whether the obstacle is present or not and if present based on the timing of the reflected waves the distance of the obstacle will be calculated. The reference signal for detecting the obstacle presence will be fixed for the vehicle height and this will be done normally for the vehicle laden condition and with low tire pressure values to avoid false sensing of the ground. When vehicle at unloaded condition, this condition fails since the vehicle height variation from unloaded to fully loaded condition varies around 10 to 15cm according to the vehicle configuration. So when the vehicle at unloaded condition will get weaker reflected waves from the considerable obstacle height and vehicle with the over loaded condition will get much stronger reflected waves from the ground. So by having the constant reference signal for the obstacle detection, either the obstacle cannot be detected at unloaded condition or the ground/very small gravels in the ground is detected as an obstacle in over loaded condition.
Similarly when the vehicle tire pressure reduces, the vehicle height goes down and the sensor will get stronger reflecting signal from ground which will start sensing the ground as the obstacle.
Various types of ultrasonic sensor for detecting obstacle has been proposed in past like United states patent number US5067115 discloses the ultrasonic obstacle sensor for sensing an obstacle on a road surface which projects ultrasonic waves in the form of pulses towards distance surface of a road in a

downwardly inclined direction and which is able to discriminate an obstacle on the road surface through the reflection waves through the comparison circuit makes a comparison between the AM modulation signal and the discrimination signal to generate an output signal representative of the presence or absence of an obstacle.
United state patent number US5076384 discloses the ultrasonic receiver mounted on the vehicle receives the ultrasonic waves reflected from the ground surface and generates the signal amplified by an amplifier. The amplified signal compared with the reference signal to detect components in the amplified signal due to obstacle on the road surface and the magnitude of the amplification factor of the reflected signal is varied according to the distance of the ground.
United states patent number US4278962 discloses the obstacle behind the car are sensed by the supersonic wave at a pre determined safety distance and the reflection there from is received to actuate the electrically the sound/ light alarm to inform the driver of the backing condition.
United state patent application US2006/0103512 A1 discloses an obstacle detection apparatus detects an obstacle to a vehicle by sensor section including the a transmitter which transmits a wave predetermined detection area, and a receiver which receives an echo of the wave reflected by the obstacle. A detection distance circuit changes the predetermined detection distance in the maximum detection distance.
European patent application EP 1750146A2 discloses the vehicle obstacle verification system and method is provided to improve the precision in which the preceding objects are identified as being a potential obstacle to a host vehicle.
To avoid this the present invention will vary the reference signal for detecting the obstacle based on the load and the tire pressure variation in the vehicle in order to have efficient sensing at all vehicle conditions.

DEFICIENCIES OF PRIOR ART
• Most of the prior art of sensing obstacle uses the constant sensing region in the vehicle with some compromise which is depend on the sensor installed height in the vehicle and the loaded and unloaded heights of the vehicle.
• Dynamic Variation in the height of the vehicle due to variation in the tire pressure and the load in the vehicle is not considered.
• Camera based system which used to detect the obstacfe and distance measure is more cost effective as individual system, but much costlier for the vehicles which already equipped with the TPMS and passenger occupant system and ultrasonic sensor.
OBJECTIVES OF PRESENT INVENTION
The main objective of the present invention is to provide a novel obstacle detecting system for automotive vehicles.
Another object of the present invention is to provide obstacle detection system that assists in reverse parking of an automotive vehicle.
Still another object of the present invention is to provide obstacle detecting system that accurately senses the distance of the obstacle without, sensing the ground at the various vehicle loaded condition and tire pressure conditions and provide alarm to the driver for the obstacle presence in the more accurate manner.
SUMMARY OF THE PRESENT INVENTION:
A rear obstacle detecting system for automotive vehicle includes and ultrasonic transmitter / receiver unit, distance detecting unit and an indicator for measuring distance to an obstacle while a vehicle is in backward or forward movement. The ultrasonic waves transmitting direction and distance

will be done adaptive by having the variation of the vehicle height to the ground reference by knowing the vehicle tire pressure of all running wheels and by knowing the total load applied on the vehicle by which the accurate sensing of the obstacle can be done at all the different heights of the vehicle.
Statement of invention
Accordingly the invention provides an Adaptive obstacle detecting system for automotive vehicles comprises an electronic control unit with display screen; number of load cell sensors mounted the below the passenger seats connected to the said electronic control unit and pressure sensors in each wheel and spare wheel communicating to the said electronic control unit through the radio communication; one or more ultrasonic sensor mounted at rear side of the vehicle for detecting obstacles connected to the said electronic control unit; and an embedded software, based on algorithms as look up table and working flow sheet diagram herein described, loaded in the said electronic control unit such that the passenger occupant system will identify the load on each location and tire pressure monitoring system will identify the pressure of the each wheel location, with the weight and tire pressure information, the vehicle height will be identified and based on the height the sensitivity (reference value) the parking assistance system at each instant, when the vehicle in engaged in reverse, the ultrasonic sensor transmit the ultrasonic waves and receives the signal back and compare with respect to the reference value at that instant and if obstacle detects then the distance of the obstacle will be calculated
DESCRIPTION OF THE FIGURES
Figure 1 shows the function flow diagram of the obstacle detection system in accordance with the present invention.
Figure 2 shows the obstacle detection system mounted in the vehicle along with different sensors.
Figure 3 shows the reference signal map for different vehicle heights.

Figure 4 shows the normal obstacle sensing mechanism in accordance with the present invention.
Figure 5 shows the reflected waveform from the obstacle at different vehicle heights.
Figure 6 shows the working flow diagram of the obstacle detection system in accordance wit the present invention.
- DETAILED DESCRIPTION OF THE PRESENT INVENTION
Referring to figure 2 the adaptive obstacle detecting system for automotive vehicles comprises an electronic control unit with display screen; number of load cell sensors(LS) mounted the below the passenger seats connected to the said electronic control unit and pressure sensors(TP) in each wheel and spare wheel communicating to the said electronic control unit through the radio communication; one or more ultrasonic sensor(US) mounted at rear side of the vehicle for detecting obstacles connected to the said electronic control unit;.
Vehicle height sag from the normal position will be identified by the load on the Front seats, Rear seats and the baggage compartment of the vehicle through the load sensor in the corresponding locations and also by identifying the tire flatness due to the tire pressure on all four tires of the vehicle. By having both of the above information the height of sensor installed location from the ground at each instant can be calculated and the sensing region (Ultrasonic wave transmitting region) can be adjusted at each instant to have the efficient sensing of the obstacle above the ground level without sensing the ground.
The total load in the vehicle can be measured by installing the load cells at the various locations in the passenger compartment like driver seat, all the passenger seats in the front and the rear, baggage compartment. With the

load values from each sensor approximate load in the vehicle will be calculated.
Tire pressure of the each wheel can be calculated by installing the tire pressure sensor in each wheel of the vehicle including spare and the tire pressure and temperature values will be transferred to the Electronic control unit through Radio Frequency communication. With the actual value of the pressure in all the wheels including the spare wheel the change in the height of the vehicle reference (Sensor installed location) point to the ground can be calculated.
Sensor installed height from the ground at unloaded condition and at optimal tire pressure is the main reference for the calculation of the vehicle height. Spare tire and its pressure value also be considered for the height calculation based on the spare tire location in the vehicle. If the spare tire is located in the rear or front, then the spare tire presence and its temperature also be considered for the calculation of the height.
Normal height is considered as the height of the vehicle at unloaded condition with all the vehicle components including spare tire installed in the corresponding location and all the tire pressure to its optimum value. Vehicle height should be calibrated for each load addition in the each locations of the vehicle for various tire pressures of each wheel and with the data look up table needs to be formed as below
Sensor locations of obstacle detection system
LS1 - Drive seat Load sensor value
LS2 - Co-driver seat load sensor value
LS3 - Rear left seat load sensor value
LS4 - Rear right sear load sensor value
LS5 - Baggage compartment left sensor value
LS6 - Baggage compartment center sensor value
LS7 - Baggage compartment right sensor value
TP1 - Front Left tire pressure
TP2 - Front Right tire pressure

TP3 - Rear left tire pressure TP4 - Rear Right tire pressure TPS - Spare tire pressure
Outputs from Look up table
VHL - Vehicle height (to the sensor location from ground) on left
VHR - Vehicle height (to the sensor location from ground) on right
Table 1 - Look up table

LSI LS2 LS3 LS4 LS5 LS6 LS7 LS8 TP1 TP2 TP3 TP4 TPS VHL VHR
0 0 0 0 0 0 0 0 X X X X X z Y
0>A1 0 0 0 0 0 0 0 X X X X X Zl Yl
A1>A2 0 0 0 0 0 0 0 X X X X X Z2 Y2
A2>A3 0 0 0 0 0 0 0 X X X X X Z3 Y3
0>A1 0>A1 0 0 0 0 0 0 X X X X X Z4 Y4
0>A1 A1>A1 0 0 0 0 0 0 X X X X X Z5 Y5
.... .... .... .... .... .... .... .... .... .... .... .... ....
0>A1 0 0 0 0 0 0 0 XI X X X X Z10 Y10
0>A1 0 0 0 0 0 0 0 X XI X X X Zll Yll
0>A1 0 0 0 0 0 0 0 X X XI X X Z12 Y12
0>A1 0 0 0 0 0 0 0 X X X XI X Z13 Y13
0>A1 0 0 0 0 0 0 0 X X X X XI Z14 Z14
.... .... .... .... .... .... .... .... .... .... .... .... .... .... ^
The look up table values will be filled up with the calibrated values and more number of the values will increase the accuracy and also increase the complexity of the system. With the load on each seat location and the pressure value of each tire location the sensor height from the ground at each sensor location value will be obtained as the output from the lookup table and the rear sensor height to the ground will be calculated approximately.

The electronic control unit loaded with an embedded software, based on algorithms as per the look up table 1 and working flow sheet diagram of fig 6.
The change in the reference signal for each vehicle height variation due to the load in the vehicle and the tire pressure is indicated in the figure 3. These reference signal were needs to be calibrated for the vehicle at different heights such that the vehicle is not sensing the ground and at the same time sensing the small obstacles. The difference in the obstacle detection for sensing various types of obstacle remain constant with the current detection.
Reflected waveform with the obstacle of height X in the ground when vehicle in fully loaded condition and vehicle at unloaded condition is shown in Figure 5. So with the variable reference signal at both the condition obstacle in the ground is detected and indicated to the user as an alert of the obstacle presence.
Once the Ignition is switched ON, the Passenger occupant system, tire pressure monitoring and Parking assistance system will powered ON and initialization of the each ECU will be done. If the initialization of Passenger occupant system or Tire pressure monitoring system fails, then the corresponding system will failed and the default weight (fully loaded) will be sent by passenger occupant system and default pressure {normal operating pressure) will be sent by tire pressure monitoring system. If the both the -systems were working, then the passenger occupant system will identify the load on each location and tire pressure monitoring system will identify the pressure of the each wheel location, with the weight and tire pressure information, the vehicle height will be identified as provided in the table 1 and based on the height the sensitivity (reference value) will be identified as in the figure 4. The reference value is sent to the parking assistance system at each instant and when the vehicle in engaged in reverse, the ultrasonic sensor transmit the ultrasonic waves and receives the signal back and compare with respect to the reference value at that instant and if obstacle detects then the distance of the obstacle will be calculated.

WE CLAIM:-
1. Adaptive obstacle detecting system for automotive vehicles comprises an electronic control unit with display screen; number of load cell sensors mounted the below the passenger seats connected to the said electronic control unit and pressure sensors in each wheel and spare wheel communicating to the said electronic control unit through the radio communication; one or more ultrasonic sensor mounted at rear side of the vehicle for detecting obstacles connected to the said electronic control unit; and an embedded software, based on algorithms as look up table and working flow sheet diagram herein described, loaded in the said electronic control unit such that the passenger occupant system will identify the load on each location and tire pressure monitoring system will identify the pressure of the each wheel location, with the weight and tire pressure information, the vehicle height will be identified and based on the height the sensitivity (reference value) the parking assistance system at each instant, when the vehicle in engaged in reverse, the ultrasonic sensor transmit the ultrasonic waves and receives the signal back and compare with respect to the reference value at that instant and if obstacle detects then the distance of the obstacle will be calculated.