A park pilot system for a vehicle and a method thereof Field of the invention

The current invention relates to parking a vehicle. The invention shows a park pilot system equipped in a vehicle and using ultrasonic or Proximity sensors to determine the parking space and autonomously guiding the vehicle to the parking space, particularly when the vehicle is in a park pilot mode or when the vehicle is an autonomously guided vehicle.

Background of the invention

This invention relates in general to a park pilot system and method for parking a vehicle fitted with such a system.

Park pilot systems are used to identify a parking space, e.g., usually a parallel space, a rear perpendicular space, or a garage parking space, and then take over the steering of the vehicle to maneuver the vehicle into the identified parking space hands free. During operation, the driver still shifts the transmission and operates the gas and brake pedals. Thus, while the steering is done automatically, the driver is still responsible for safe parking of the vehicle. One known vehicle park pilot system is disclosed in U.S document 6,948,729.

Description of the invention

The core of the current invention is to park a vehicle in a parking slot. According to the present invention, the desired angle of trajectory for parking maneuver is determined by the features of the independent claims. The invention shows a method in a park pilot system equipped in the vehicle. The park pilot system determines the parking space using ultrasonic or proximity sensors and autonomously guiding the vehicle to the parking space, particularly when the vehicle is in a park pilot mode or when the vehicle is an autonomously guided vehicle. The vehicle is guided to the parking space at least in one maneuver by progressively applying break on one of the wheel(s) either to the left or right side of the vehicle and simultaneously applying acceleration to other wheels on the other side to achieve the pre-determined trajectory during the execution of the parking maneuver.

The required angle of trajectory is achieved by means of,

1. Progressively applying a break on one or set of wheels either on left side or right side of the vehicle and acceleration on other set of wheels.

2. The movement of the vehicle in the desired trajectory is corrected by reading the distance that the vehicle has been travelled in the predetermined trajectory of the target parking space. Constant course correction is done with respect to the predetermined trajectory with the aid of sensors inputs and distance travelled information.

The parking maneuver may require more than one maneuver to guide the vehicle to a parking space. So the desired angle of trajectory is achieved for each maneuver by continuously applying break on one of the wheels and simultaneously applying acceleration to the other wheels. For example, if the vehicle is required to make a left turn, park pilot system activates the left rear brake, which will help turn the vehicle left. The current invention applies appropriate brake force and acceleration to maneuver the vehicle into the parking space effectively.

Short description of the drawings

An exemplifying embodiment of the invention is explained in principle below with reference to the drawings. The drawings are,

Figure 1 shows a block diagram of the device of the current invention; Figure 2 shows a typical city street scenario, showing an example of the operation of the device of current invention; and

Figure. 3 illustrate movement of the vehicle with respect to the trajectory of the parking space.

Description of the Embodiments

Figure 1 shows a block diagram of a park pilot system 100 of the current invention which can be equipped in a vehicle V. The system 100 comprising a sensing means 30 for determining a target parking space 500, 550 in the parking area, a parking mode switch 40 to switch between a manual or automatic parking mode, a trajectory determining means 50 to determine an angle of trajectory, a braking system 60 for controlling the traction of the wheel, an accelerating system 70 to accelerate the vehicle for required speed/Velocity. The parking mode switch 40 can be placed on the dash board of the vehicle V.

In the illustrated embodiment, the sensing system 30 receives input signals from plurality of sensors that includes ultrasonic sensors or proximity sensors 10, 20. The ultrasonic sensors may be located on a side(s) of a front and/or rear side of the vehicle. The ultrasonic sensors 10, 20 also indicate the movement of the vehicle in the direction of the vehicle travel and help to maneuver the vehicle in a trajectory.

The trajectory determining means 50 receives input from the sensing system 30 to determine a trajectory of parking space. The trajectory of the parking space is divided into the sub trajectory and calculates an angle of the trajectory that is required to maneuver the vehicle in the trajectory of the parking space 500 based on the direction of the movement of the vehicle. The angle of the trajectory is calculated with respect to the axis of the vehicle and required trajectory of the parking space 500. The braking system 60 receives the input from the trajectory determining means 50 and calculates for which wheel the breaking is required so that other wheels can be moved for the desired angle of trajectory based on the direction of the movement of the vehicle. The breaking system 60 applies break on at least one wheel so that other wheels can be moved to maneuver the vehicle in the trajectory of the parking space 500.

The accelerating system 70 receives input signals from sensors positioned at the wheels W12, W14 for determining how much distance the vehicle has to move or has been moved in the trajectory of parking space 500 after applying brake on one of the wheels. For example the distance travelled by the vehicle can be calculated by measuring the circumference of the wheel by reading a wheel impulse counter determined using I R sensors or by calculating the velocity of the vehicle using proximity sensors.

Figure 2 shows an example of a typical scenario of a city road wherein the vehicle V equipped with the park pilot system 100, is travelling. The vehicle V assumes different positions, namely position A, position B and position C along with its forward movement. The sensing system 10 receives position of the vehicle and from the ultrasonic or proximity sensors located on the periphery of the vehicle determines distance between the vehicle and the at least one point 500, 550 in the vicinity of the vehicle. At least one point 500, 550 in the vicinity of the vehicle can be another vehicle 550 parked by the side of the road or an empty parking space 500 on the road. After detecting the empty parking space 500 of required slot length, the vehicle V is ready for parking in the target parking space. The vehicle V can be operated to park in the automated mode by switching the parking mode switch 40 and by engaging the gear in the reverse position.

The velocity of the vehicle V is necessary for the park pilot system for parking the vehicle

V automatically. The park pilot system 100 calculates the distance by which the vehicle

V has to move back, to maneuver the vehicle V into the parking space 500 for example on the right side based on the parking space length and the vehicle length d _L . The proximity sensors 10, 20 of the current example continuously measure a distance between the vehicle V and the points 500, 550 in the vicinity of the vehicle V. The distance is measured for each sample of the operation of the proximity sensors 10, 20. The distance varies for each point 500, 550 in the vicinity of the vehicle V. The breaking system applies a break on one of the front or rear wheel or set of the wheels to move the vehicle in the trajectory 1000.

Figure 3 illustrate movement of the vehicle with respect to the trajectory 1000 of the parking space 500. As shown in the Figure. 3, the vehicle trajectory 1000 is divided into different sub trajectories SO, SI, S2, S3, S4 and S5 etc based on the length of the trajectory 1000. At each sub trajectory, the trajectory determining means 50 receives information about the trajectory 1000 of the parking space and the axis of the vehicle from the sensing system 30 and calculates the required angle of trajectory (x, y, xl) with respect to the vehicle axis by which the vehicle maneuver is required. In this example of Figure 3, the vehicle with rear wheel drive is illustrated only for illustration. The invention can be modified and applied to any other type of vehicle wheel drive. At the sub trajectory SO, the vehicle is required to maneuver at the angle of trajectory x, hence the breaking system is triggered to apply break on rear left wheel and apply acceleration on other wheels until the required angle of trajectory x is achieved. Once the angle of trajectory x is achieved the vehicle has been maneuvered until the position PI in the trajectory S2 by releasing the break on the wheel and accelerating. At the position PI in the trajectory S2, the vehicle V is required to maneuver at the angle of trajectory y and hence the break is applied on the right wheel to maneuver the vehicle to reach the trajectory S2. Likewise the vehicle is maneuvered to the parking space 500 through the sub trajectories S3, S4 and S5 etc by calculating the required angle of trajectory for each sub trajectory and by applying break on one wheel and accelerating on other wheels. The movement of the vehicle in the desired angle of the trajectory x, y, xl is progressively corrected in the sub trajectories for the trajectory of the target parking space. The movement of the vehicle in the desired trajectory is corrected by reading the distance that the vehicle has been travelled in the trajectory of the target parking space. The distance travelled by the vehicle in the trajectory is calculated by measuring the circumference of the wheel or by measuring velocity of the vehicle using proximity sensors. The circumference of the wheel is measured using the I R sensors positioned at the wheels W12, W14. Constant course correction is done with respect to the predetermined trajectory 1000 with the aid of sensors inputs and distance travelled information derived from a wheel impulse counter W12, W14 or by measuring velocity of the vehicle using proximity sensors. Thus the vehicle has been maneuvered to the target parking space 500 in the determined trajectory 1000 by applying the brake to at least one wheel of said vehicle and simultaneously applying acceleration to other wheels of said vehicle to achieve the desired angle of the trajectory. Upon reaching the parking space 500, the driver can takeover the control and park the vehicle in the desired position.

It must be understood that the embodiments explained in the above detailed description in only illustrative and does not limit the scope of this invention. The scope of this invention is limited only by the scope of the claims. Many modification and changes in the embodiments aforementioned are envisaged and are within the scope of this invention.