【正文】 ed that mimics the kinematics of a human rock climber who uses four limbs to climb and implements the method used by cats to climb on trees utilizing their claws. The robot that was designed is termed CLIBO (claw inspired robot). A robot prototype was constructed for the purpose of demonstrating our concept. Using a kinematics model, the lootion algorithm that was developed as part of this work bines control of the four legs with an ability to utilize smart actuators. Our experimental results with CLIBO have shown that reliable wallclimbing is feasible. The unique design of the robot provides it with maneuvering capabilities, on the one hand, and the ability to control its position and force distribution, on the other. A robot that can vertically and autonomously move vertically along a rough surface such as stucco, offers considerable military and civilian advantages. Positioned high on a building, the robot, serving as an observation platform, could provide valuable military intelligence as well as assist in search and rescue operations. Such a robot could also be used for unmanned sweeps of hostile areas and serve as a platform for carrying firearms and explosives. In terms of civilian use, the robot could be used in construction to signal back the progress or state of various operations being implemented at dangerously high levels. The first part of this paper presents a review of the consideration in the robot’s design that led to its kinematic structure. In the second part we review the mathematical model of the robot, describing the kinematics and static model derived from its design. In Section 3 we discuss a motion planning algorithm based on grip quality measures and robot kinematics. Section 4 presents the implementation of the design and the motion planning also present here the prototype robot that has been built and discuss various wallclimbing experiments that were carried out with the prototype. 2. Robot design and analysis In order to achieve a working robot capable of climbing rough surfaces, CLIBO’s structure was developed in such a way that when activated it would mimic a rock climbing technique of climbing using four limbs. This section reviews the robot’s design, its physical structure and the kinematic and static models. 16 . Robot design The robot consists of four legs which are arranged symmetrically around the robot’s central body. Each leg has fivedegreesoffreedom (DOF). Fig. 1 describes the design of a leg. Four of the DOFs are motorized and the fifth, which is in the gripping device mounted on the tip of the leg, is a passive DOF. The first two DOFs,whose axes are perpendicular to the wall, enable the robot to move forward. These two DOFs are also responsible for controlling the attachment of the claws to the wall by pulling the endeffectors (EE),described below, down toward the floor and checking the reaction forces. The two remaining motorized DOFs whose axes are parallel to the wall’s plane are designed for determining the distance of the robot from the wall (Motor 3) and the angular constraint for the EE(Motor 4). This design of the leg provides the robot with good gait first two motors in each leg drive the robot’s the attachment of the hooks and upon determination of the distance from the wall (by Motors 3 and 4) of every leg, the robot’s movement is made by the first two motors in each leg. This movement is similar to the movement of rockclimbers who use their fingers to grasp cracks in a rock face and activate their shoulder and elbow muscles to advance. The structure of the robot allows it to move in any desired direction (360176。. We use frame B to represent the position of the leg EEs in relation to the current central body position of the robot. However,because the legs are similar, all the legs movements will be controlled in frame L by the same global function . Inverse kinematics To position the EE at a desired location, we use the inverse kinematics (IK) which defines the legs’ matching angles. This means that a certain configuration would give the desired position of the leg EEs. The IK is used for a single leg relative to CLIBO’s central body. The IK is used to reach a desired EEs position in relative to the central body according to the legs’ matching orientation of the EE remains constant due to the balancing weight mentioned previously. The calculation of the IK is made with the assumption that the central body’s orientation remains vertical at all time. This assumption is accurate due to orientation angle correction of the central body which will be made within the motion algorithm, as will be 20 detailed later. Moreover, the distance of the central body from the wall is constrained to the defined value Z. By construction of the leg, the two lateral joints are responsible for the distance from the wall and the approach angle of the the two joints which are closer to the central base are responsible for the location of the contact point in the X–Y these constraints and assumptions, there are four different solutions for the desired angles, two for θ1,θ2 and two for θ3, , as we search for the same configuration solution for all legs, frame L of every leg is fixed as a mirror view to its the position of the EE as (X, Y)T , the inverse kinematics,puted using the leg geometrics, is calculated in frame L. Let variable E be the projection of the distance from frame 2’s origin to the EE on the global frame’s x–y plane (Fig. 3). From the law of cosines, θ2 is: From the law of sines, θ1 will be: when the leg is attached to the wall, the distance from the wall Z remains constant. Therefore, the sum of θ3 and θ4 which defines the distance Z, remains constant and is given by κ. From (2): From (6), we can extract θ3: Therefore, θ4 will be: This method