In 2013, my friends and I designed a new type of three-legged robot design scheme. Spatial crank rocker mechanism (RSSR) is used to transfer the motor rotation into a leg swinging in mechanical design. ARM Cortex-M3 microprocessor, 2.4GHz wireless communication module and magnetic encoder are used in controller design. Proportional and differential (PD) closed loop control algorithm is used to the control loop of the actuator. The robot is capable of diverse movement, such as straight walk, curve walk, spot turn, jumping and so on. It has a broad application prospect.
The whole mechanical system can be divided into driving gear, transmission system and actuator. The coreless motor and the model ship battery are selected for driving gear. A set of three-level gear transmission system is used to reduce the output rotate speed and increase the output torque. The module of the gear is 0.5 and the resultant gear ratio is 85.5. RSSR is used as actuator to will the motor rotation into a leg swinging in mechanical design. The above photos shows the gear transmission system.
The electric control system architecture of the Trinibot is built based on dual ARM Cortex-M3 [3] microcontrollers manufactured by STMicroelectronics. The motion control of three brushed DC motors, high level gait planning , wireless communication and tasks scheduling are handled by dual ARM cortex-M3 microcontrollers. In addition, the minimum volume and weight of The Trinibot’s DC motor servo driver architecture benefit from the Magnetic Rotary Encoder manufactured by Austriamicrosystems. The integration of all electronic elements in a dual-layer PCB improves the compaction, stability and reducing the weight of the robot. For detial, please read my paper “A New Design of Three-Legged Robot of Mechanical and Control System”. There is a demo of my trinibot below.