Bionic Control Of Gecko Mimicing Robot: From Behavior Observation To Control Realization

Quadruped gecko mimicking robot has merits of good terrain adaptability, obstacles avoidance, and multiple locomotion type which wheeled sports tools don't have. With little shape and good concealment, the robot has good application prospects in military reconnaissance, research and rescue in disaster and narrow space, and other unstructured circumstances.Motion behaviors of gecko on horizontal and vertical surface with trotting and walking gait were observed by three dimensional motion observation systems. The amplitudes of uplift and falling down of fore thigh with trotting gait are larger than that with walking gait when moving on horizontal surface, consequently, the probabilities of collision between limbs and obstacles in swing phase and friction between contact surface and body in stance phase were reduced. The uplift angle is smaller than walking gait, and limbs need only to overcome the gravity to support the body off the ground and impel the body forward, which makes the motion style of limbs agility. Range of swing angle increase obviously with speed up on vertical surface, and which represented mainly on the forward direction and little on the backward direction. In order to reduce the overturn moment, limbs in stance phase move under the plane which paralleling to the body plane and cross the hip joint as far as possible to deduce the distance between body and the surface. Hind limbs in swing phase close to the body to reduce the inertia. By analyzing the trajectory of foot tips when trotting on two surfaces it was found that fore and hind limbs remain the same step length during locomotion despite of the different size. The transition of motion direction of feet was finished in swing phase and the uniform swing backward had begun before turning into stance phase, which supported bionic basis and inspiration for the motion coordination of robot control.The mechanism of gecko mimicking robot and single leg kinematics were analyzed. The relationship between angular space and work space of foot tip relative to shoulder (hip) joint was calculated. A trajectory plan method of foot tip was put forward according to the result of behavior observation experiments, which supported theoretical basis for the motion coordination of robot control.The robot control system architecture was designed according to the characteristics of the quadruped robot. Distributed control system was used. The motion of each leg was controlled by one leg controller module. The host controller was responsible for receiving and parsing of control instructions, which also plans and coordinates the motion of four legs. Motion control instructions were sent by wireless communication. Two kinds of control system were established according to different motion scheming method of foot tip, and the wireless motion control system were realized successfully.Commercial wireless mobile service was used to build the wireless remote transmission system of video image and control instructions. A strong performance and high speed dual core DSP processor and a CDMA wireless communication module were used in this system. In the embedded operating system platform, Analog camera signals were digitalized by a video decoder, and converted into suitable size for viewing by the processor. Then the video was compressed into MPEG-4 format. Data stream was sent out through the CDMA wireless module. The client software receives video data by a communication linkage established between the client software and robot. The remote monitoring and control was realized by adjusting the motion instructions according to the environments the robot working in.Through the above jobs, motion behaviors of gecko, robot kinematics, motion control system, wireless remote transmission of video image and motion control instructions were studied, and the wireless remote monitoring and motion control of robot were realized.