2. LITERATURE SURVEY
[1] Roh J, Woojin Chung (2010)
Reversing control of a car with a trailer using a Driver AssistanceSystem :
A passive trailer system can be used efficiently for transportation tasks. However, backward motion control of a trailer system is difficult because it is an open loop unstable system. In our previous researches, we have shown that n passive trailers can be successfully controlled by an ommni-directional or a two-wheel-differential mobile robot. However, a passive trailer system pulled by a car is widely used in practical environments. Unlike mobile robots, a car- like mobile robot has nonholonomic constraints and limitation of the steering angle. In this paper, we tried to solve the backward motion control problem of the trailer system with a car by proposing two strategies.
First, we proposed Driver Assistance System (DAS). By using the DAS, a driver can control the trailer system as a forward motion control instead of a backward motion control directly. A driver only secure the rearviewof the last passive trailer, and select the control input to drive the last passive trailer. The DAS converts the control input of a driver into the velocity and a steering angle of a car by inverse kinematics. The DAS can be achieved combining several electronic devices which are recently embedded in a can in general. Second, we proposed a kinematic configuration which is connecting a passive trailer to the front bumper of a car for increasing the feasible region of backward motion control.
Performances of the proposed control strategy and the kinematic configuration are verified by theoretical verifications and experimental results.
[2] Sears Williard T (1925)
1. A ratchet and pawl mechanism comprising in combination, a ratchet wheel, an oscillating arm having a pawl thereon adapted to engage and rotate the ratchet wheel, an intermediate pawl member on the arm, an extension on the intermediate pawl member, and adjustable means engaging said extension and causing said intermediate pawl to be oscillated and oscillating the pawl out of driving engagement with the ratchet wheel at any predetermined point in the stroke of the oscillating arm.
2. A ratchet and pawl mechanism comprising in combination, a ratchet wheel, an oscillating arm having a pawl thereon adapted to engage and rotate the ratchet wheel, said pawl comprising two pivotally connected members having spring means to hold them in operative relative position, an extension on oneof said members, and adjustable means engaging said extension adapted to oscillate the othermember out of driving engagement with the ratchet wheel at any predetermined point in the stroke of the oscillating arm.
3. A. ratchet and pawl mechanism comprising in combination, a ratchet wheel, an oscillating arm having a pawl thereon adapted to engage and rotate the ratchet wheel, said pawl comprising two pivotally connected members having spring means to hold them in operative relative position, an extension on one of said members, adjustable means engaging said extension adapted to oscillate the other member out of driving engagement with the ratchet wheel at any predetermined point in the stroke of the oscillating arm, and means to clamp the adjustable means in any desired position.