This paper presents a method to measure gripping force of a bipedal wall-climbing robot (WCR) with spiny toe pads. The spiny toe pad is designed based on inspiration of an insect’s tarsal system. Each foot of the robot consists of a pair of opposed linear spiny arrays. The foot employs a pulley system to actuate the arrays via four pairs of tension and compression springs. Two Hall effect sensors are embedded into the robot feet to sense the gripping force by detecting the linear deformation of the springs. The two Hall effect sensors are calibrated and the relationship between the voltage signal output of the sensors and displacement is established before measuring gripping force. Then the consistency and accuracy of Hall effect sensor measurement method are verified by comparing with a commercial force sensor. A horizontal crawling test of the WCR is carried out and the gripping force verse time when the WCR moves. The experimental results show that the measured force history is in accordance with the actual movement states.

In this article, a novel wall-climbing locomotion mechanism, which can adapt multiple wall surfaces is developed to imitate the special animals, such as geckoes or flies. The spiny and adhesive belts are adopted in this robot to implement climbing on different kinds of wall surfaces instead of the vacuum generator for moving quietly and quickly. The switching mechanism is brought out to realize the belts switching between different surfaces, and a tail made up of two torsional springs and a supporting part is designed to overcome the robot’s overturning moment. So the mechanical system of the robot consists of four parts: the power and drive system, the moving mechanisms (spiny and adhesive), the switching system and the tail. Then the virtual prototyping of the robot with multi-locomotion modes is brought out, and the different gaits on the rough surface, the smooth surface and the transition process are analyzed. During the spine gait using the spine belts, the adhesive force should overcome the robot gravity and drive it, so the drive torque can obtained by building the force balance equations of the robot, which include the supporting forces of the spine belts and the tail. During the adhesive gait using the adhesive rubber belts, the force balance equations should include the supporting forces of the adhesive belts and the tail. And during the transition gait, the force balance equations include all of the above forces. So the mechanical model of the robot can be built according to the above analysis. Finally, the experimental prototype of the wall-climbing robot is manufactured and the wall-climbing experiments are carried out to testify its functions. The experiments show that the robot can adapt to different wall surfaces, and the torque parameters obtained based on the dynamics model can ensure the robot to locomote stably.