Bingtuan Gao

Development of a miniature self-stabilization jumping robot

We present the design and implementation of a new jumping robot for mobile sensor network. Unlike other jumping robots, the robot is based on a simple two-mass-spring model. After we throw it on ground, it can stabilize itself and then jump once. The detailed mechanism design including the load holding and self-stabilization are presented. Jumping heights and distances with different robot weights are measured and compared with calculated values from the two-mass-spring model.

Development of a controllable and continuous jumping robot

A miniature robot with continuous jumping ability is presented in this paper. The robot has a dimension about 6cm×8cm×2cm and weighs 20 grams. To achieve continuous jumping, various mechanisms are needed including the jumping mechanism, energy store and release mechanism, self-righting mechanism, and jumping direction changing mechanism. The design and analysis for those mechanisms are elaborated in this paper. Moreover, implementation and experimental results are also presented. It is shown that the robot can jump higher than 55cm with a 75° takeoff angle. The robot can be used as mobile sensors and deployed in the areas of rugged terrain and natural obstacles which are not suitable for sensors with wheels.

Energy-based control design of an underactuated 2-dimensional TORA system

The translational oscillation with a rotational actuator (TORA) system has been used as a benchmark for motivating the study of nonlinear control techniques. In this paper, modeling and control of a novel 2-dimensional TORA (2DTORA) are presented. The 2DTORA is an underactuated mechanical system which has one actuated rotor and two unactuated translational carts. The dynamics of the 2DTORA system is derived based on Lagrange equations. The total energy of the system is employed to show the passivity property of 2DTORA, and then a simple state feedback control algorithm is developed based on a proper Lyapunov function including energy item. Finally, simulation results are demonstrated.

A Humanoid Neck System Featuring Low Motion-Noise

This paper presents our recently developed humanoid neck system that can effectively mimic motion of human neck with very low motion noises. The features of low motion noises allows our system to work like a real human neck. Thus the level of acoustic noises from wearable equipments, such as donning respirators or chemical-resistant jackets, induced by human head motion can be simulated and investigated using such a system. Our low motion-noise humanoid head/neck system is based on the spring structure, which can generate 1 degree of freedom (DOF) jaw movement and 3DOF neck movement. To guarantee the low-noise feature, no noise-makers like gear and electro-driven parts are embedded in the head/neck structure. Instead, the motion is driven by seven polyester cables, and the actuators pulling the cables are sealed in a sound insulation box. Furthermore, statics analysis and motion control design of the system have been presented. Experimental results clearly show that the head/neck system can greatly mimic the motion of human head with an A-weighted noise level of 30 dB or below.

Combined Inverse Kinematic and Static Analysis and Optimal Design of a Cable-Driven Mechanism with a Spring Spine

Abstract A special humanoid neck with low motion noise requirements yields a cable-driven parallel mechanism to imitate the rotational motion of a human neck. The fixed base and moving platform of the mechanism are connected by four cables and a column compression spring. The four cables are actuated separately, while the spring can support weight on the moving platform. Although similar mechanisms exist in the literature, the analysis of them is scarce because a flexible spring instead of a rigid kinematic chain is used as the spine. With the spring’s lateral buckling motion, a new approach must be adopted to solve the kinematics. In this paper, we propose a method that combines the kinematics with the statics to solve them simultaneously. The configuration of the moving platform is parameterized with four parameters, one of which is considered as parasitic motion. Using the spring’s lateral buckling equation, we can obtain the parasitic motion and solve the inverse position problem. The optimal design for cable placements is then performed to minimize the actuation force. The method in this paper provides a novel way to analyze parallel mechanisms with a spring spine and it can be applied to other mechanisms with flexible spines.

Design and testing of a controllable miniature jumping robot

Mobile sensors with jumping ability provide several advantages compared with the traditional wheeled sensors such as ability to move in rugged terrain. A controllable jumping robot for this purpose is described in this paper. The robot has dimension about 9.5cm×9cm×3cm and weighs 54.1 grams. It can perform the jumping process continuously. This paper focuses on the mechanisms to achieve such a continuous jumping ability, including the jumping mechanism, energy store and release mechanism, and self-righting mechanism. Detail implementation and experimental results are also given in this paper. It is shown that with a 75° takeoff angle, the robot can jump about 20cm in height.

High-accuracy visual/PSD hybrid servoing of robotic manipulator

This paper presents a new and effective multisensor based control strategy for high-accuracy/precision and high-efficiency automatic robot localization and calibration. The strategy combines both coarsely visual servo and fine position-sensitive detector (PSD) servo control methods. In a large field of view, an image-based visual servo control system is developed to roughly guide the laser beam, which is from a single laser pointer mounted at the end-effector of robot, to project to the high-resolution segmented PSDs. Once the laser spot is projected onto the active area of PSD, the control will be switched to the high-resolution PSD feedback and servoing for fine positioning. The experimental results conducted on an ABB industrial robot IRB1600 verify the effectiveness of the developed visual/PSD hybrid servo controllers as well as demonstrate that the high accuracy 30 mum of robot localization can be approached. The development of the hybrid control system and method will be a major step for achieving high-performance automatic robot calibration.

Development and sensitivity analysis of a portable calibration system for joint offset of industrial robot

This paper describes our updated system for industrial robot joint offset calibration. The system consists of an IRB1600 industrial robot, a laser tool attached to the robots end-effector, a portable position-sensitive device (PPD), and a PC based controller. By aiming the laser spot to the center of position-sensitive-detector (PSD) on the PPD with different robot configurations, the developed system ideally implements our proposed calibration method called the virtual line-based single-point constraint approach. However, unlike our previous approach, the calibration method is extended to identify the offset parameters with an uncalibrated laser tool. The position errors of the PPD and the sensitivities of error in the PSD plane to the variation of joint angles are analyzed. Two different robot configuration patterns are compared by implementing the calibration method. Both simulation and real experimental results are consistent with the mathematical analysis. Experimental results with small (10−3−10−2) mean and standard deviation of parameters error verify the effectiveness of both the sensitivity analysis and the developed system.

Passivity-based control of two-dimensional translational oscillator with rotational actuator

An underactuated two-dimensional translational oscillator with rotational actuator (2DTORA) consisting of an actuated rotational proof-mass and two unactuated translational carts is presented. Passivity-based control design is employed for 2DTORA based on its Euler–Lagrange structure and passivity property. Firstly, the dynamics of 2DTORA are derived based on Euler–Lagrange equations. Motivated by constructing a damped close-loop Euler–Lagrange system, the controller dynamics is designed to shape the potential energy and inject the required damping. As a result, the designed controller stabilizes the underactuated 2DTORA with the feedback of the rotational actuator’s position only. Moreover, by modifying controller dynamics with a saturation function, the control input can be constrained to certain bounds. Finally, simulation results demonstrate the feasibility and effectiveness of the proposed controllers.

Development of a low motion-noise humanoid neck: Statics analysis and experimental validation

This paper presents our recently developed humanoid neck system that can effectively mimic motion of human neck with very low motion noises. The feature of low motion noises allows our system to work like a real human head/neck. Thus the level of acoustic noises from wearable equipments, such as donning respirators or chemical-resistant jackets, induced by human head motion can be simulated and investigated using such a system. The objective of this investigation is to facilitate using head-worn communication devices for the person who wears the protective equipment/uniform that usually produces communication-noise when the head/neck moves. Our low motion-noise humanoid neck system is based on the spring structure, which can generate 1 Degree of Freedom (DOF) jaw movement and 3DOF neck movement. To guarantee the low-noise feature, no noise-makers like gear and electro-driven parts are embedded in the head/neck structure. Instead, the motions are driven by seven cables, and the actuators pulling the cables are sealed in a sound insulation box. Furthermore, statics analysis of the system has been processed completely. Experimental results validate the analysis, and clearly show that the head/neck system can greatly mimic the motions of human head with an A-weighted noise level of 30 dB or below