Chuanwu Cai

A Modular Biped Wall-Climbing Robot With High Mobility and Manipulating Function

High-rise tasks such as cleaning, painting, inspection, and maintenance on walls of large buildings or other structures require robots with climbing and manipulating skills. Motivated by these potential applications and inspired by the climbing motion of inchworms, we have developed a biped wall-climbing robot-W-Climbot. Built with a modular approach, the robot consists of five joint modules connected in series and two suction modules mounted at the two ends. With this configuration and biped climbing mode, W-Climbot not only has superior mobility on smooth walls, but also has the function of attaching to and manipulating objects equivalent to a “mobile manipulator.” In this paper, we address several fundamental issues with this novel wall-climbing robot, including system development, analysis of suction force, basic climbing gaits, overcoming obstacles, and transiting among walls. A series of comprehensive and challenging experiments with the robot climbing on walls and performing a manipulation task have been conducted to demonstrate its superior climbing ability and manipulation function. The analytical and experimental results have shown that W-Climbot represents a significant advancement in the development of wall-climbing robots.

Climbot: A modular bio-inspired biped climbing robot

High-rise tasks in agriculture, forestry and building industry requires robots possessing climbing function. Motivated by these potential applications and inspired by the climbing motion of animals such as inchworms, we have developed a novel biped climbing robot - Climbot. Built with a modular approach, the robot consists of five 1-DoF joint modules connected in series and two special grippers mounted at the ends. With this configuration, Climbot is able not only to climb a variety of media, but also to grasp and manipulate objects, and hence is a “mobile” manipulator. In this paper, we first introduce the development of this novel robot, and then illustrate three climbing gaits based on the unique configuration of the robot. Experiments of climbing poles are carried out to verify the climbing functions and to demonstrate potential application of the proposed robot.

W-Climbot: A modular biped wall-climbing robot

Although a large number of wall-climbing robots have been developed in the past decades, most of them suffer from shortcomings such as poor ability to omni-directional locomotion, lower capability to transit between walls and to negotiate obstacles on the walls. To overcome these drawbacks, we have developed a novel biped wall-climbing robot - W-Climbot using modularization method. Consisting of an arm as the main body and two vacuum suckers at the two ends, W-Climbot has great mobility on walls and potential manipulation function. In this paper, the development of W-Climbot is briefly introduced, and then the suction force model for suction module design is presented. The superior ability to transit between walls and to traverse and step over obstacles is analyzed. Experiments are carried out to verify the effectiveness of the system design and to demonstrate basic features of the novel robot.

An intelligent environmental monitoring system based on autonomous mobile robot

Monitoring indoor environmental state of large communication rooms, warehouses and power stations is an important task. Based on mobile robotics, we have developed an intelligent environmental monitoring system. In this system, a mobile robot carrying a number of sensors autonomously navigates and dynamically sample the environmental data including the temperature, humidity and airflow velocity. The system outputs the environmental parameters in appropriate modes such as clouds. In this paper, we present the development of this monitoring system, its working principle and application effectiveness. It has been shown how a mobile robot can be used to as a novel application in industry environments.

A biologically inspired miniature biped climbing robot

Inspired by the motion patterns of inchworms, a miniature biped climbing robot is developed with modularization method for some tedious and dangerous high-rise tasks. This inchworm-like mini-robot consists of several modules including I-typed joint modules, T-typed joint modules, and gripper modules, which are all driven by small RC servo motors. In this paper, the development of the robot prototype with biomimetic and modular methods is presented, and two feasible gaits of the mini-robot are proposed for climbing poles, trees and trusses. The climbing ability of such biped robot is verified through simple experiments. It is shown that the locomotion function of some biped climbing animals such as inchworms can be easily implemented by simple mechatronic systems.

Stability of biped robotic walking with frictional constraints

Tipping-over and slipping, which are related to zero moment point (ZMP) and frictional constraint respectively, are the two most common instability forms of biped robotic walking. Conventional criterion of stability is not sufficient in some cases, since it neglects frictional constraint or considers translational friction only. The goal of this paper is to fully address frictional constraints in biped walking and develop corresponding stability criteria. Frictional constraints for biped locomotion are first analyzed and then the method to obtain the closed-form solutions of the frictional force and moment for a biped robot with rectangular and circular feet is presented. The maximum frictional force and moment are calculated in the case of ZMP at the center of contact area. Experiments with a 6-degree of freedom active walking biped robot are conducted to verify the effectiveness of the stability analysis.

Joystick-based Control for a Biomimetic Biped Climbing Robot

A joystick-based control method is studied for Climbot,which is a novel 5-DoF(degree of freedom) biomimetic biped climbing robot.The kinematics and the available grasping area of the robot are analyzed firstly.And then,according to the characteristics of the robot biped climbing by switching its fixed-gripper,an intuitional joystick-based operating mode is proposed,in which different operating coordinates are defined for corresponding climbing gaits,and a matrix transform algorithm is presented to keep the robot coordinate system unchanging after switching its fixed-gripper.Finally,road-pole climbing experiments with three gaits(including inchworm-like,turning-around and turning-over gaits) and an application demonstration are carried out to verify the effectiveness of the presented joystick-based control method.

Modeling and planning for stable walking of a novel 6-DOF biped robot

Most of current biped robots are active walking platforms. Though they have strong locomotion ability and good adaptability to environments, they have a lot of degrees of freedom (DoFs) and hence result in complex control and high energy consumption. On the other hand, passive or semi-passive walking robots require less DoFs and energy, but their walking capability and robustness are poor. To overcome these shortcomings, we have developed a novel active biped walking robot with only six DoFs. The robot consists of an arm as the main body and two wheels as the feet. With this novel configuration, the robot can walk in several special walking gaits different from those of traditional biped robots. And for these gaits, the criterion of stable walking needs to be developed and analyzed. In this paper, the biped robot is introduced, walking gaits, dynamic stability and walking pattern with moment compensation are presented. Simulations and experiments are carried out to verify the effectiveness and to illustrate the unique features of this novel walking robot.

Evaluation of graspable region and selection of footholds for biped pole-climbing robots

For biped pole-climbing robots (BiPCRs), footholds, indicating a sequence of discrete gripping points from the start to the goal, are necessary for travelling in trussed environments. Graspable region in each climbing cycle is the valuable priori knowledge for consideration of selecting specific grasping point. However, how to evaluate all the grasps within the graspable region so as to provide a reasonable grasp selection strategy, is an interesting and pending issue. In this paper, we present three criteria to evaluate grasps considering the characteristics of the climbing motion of BiPCRs. Based on these criteria, we also propose two strategies to optimally select a grasp from the graspable region. An algorithm is presented for BiPCRs to perform foothold planning in trusses. Simulations are carried out to verify the effectiveness of the criteria, the selection strategies and the foothold planning algorithm.

MiniBibot:A Miniature Modular Biped Robot with Multi-locomotion Modes

Inspired by the climbing motion of animals such as inchworm,a miniature biped robot with multi-locomotion modes is developed,named MiniBibot,driven by servo motors.The robotic system is designed and built with modular methodology.The processes and methods to develop users program are illustrated with the control instance of climbing poles. According to the robots configuration,five realizable locomotion modes are proposed,and their features and applications are analyzed.A series of experiments with this miniature biped robot are conducted to illustrate and verify the effectiveness and feasibility of the proposed robotic system and its multi-locomotion modes.