Experimental Investigation into The System Performance of Rack and Pinion Gear Using Inverse Kinematics for Lifting Mechanism in ABU Robocon Mobile Robot

In every team of the ABU Robocon competition, there are Elephant Robots (ER) and Rabbit Robots (RR) where each robot has different obstacles. A 20 cm high stairwell is one of the RR obstacles. To get past the obstacle, the RR robot needs a stair-climbing system, such as 1-DOF arm and lifting mechanism. This paper discussed kinematics for control and comparison of the performance in the lifting mechanism. The lifting mechanism uses a rack and pinion gear transmission system. The Inverse kinematics formula is obtained from rack and pinion gear kinematics. System design of the lifting mechanism using DC Motor as a driven, magnetic rotary encoder sensor as feedback, and microcontroller as a setpoint and sensor reading processor. The obtained kinematics formula has been tested within the real condition. In the test, the obtained distance and angle are compared with the kinematics calculation result. The error percentage of rotation angle to the setpoint from inverse kinematics is -1,8% with an average error of $-13,199^{\circ}$. In a comparison of system performance, inverse kinematics is used to drive the lifting system to a certain pinion gear angular rotation as a setpoint. The system performance tested with no-load condition. To get better performance, the lifting system is given by PID control. The system performance test results show that the system without PID control performs better in reaching and maintaining the position to the setpoint.