A humanoid robot capable of carrying heavy objects

Robotica ◽  
2010 ◽  
Vol 29 (5) ◽  
pp. 667-681 ◽  
Author(s):  
Hyeung-Sik Choi ◽  
Wonhyun Na ◽  
Dongwan Kang

SUMMARYA new type of 28-DOF (degree of freedom) full-size humanoid robot, driven by a closed-chain type of joint actuation system, is developed in this paper. Each leg of the robot is composed of six joints, where three are at the hip, one is at the knee, and two are at the ankle. The robot has six joints for each arm, one balancing joint, and three joints for the head, with two cameras. The weight of the robot is 75 kg, and its height is 168 cm.The actuation systems of the pitching joint for the arms and legs of the robot are designed based on a closed-chain mechanism composed of four bar links driven by a ball screw, and each leg of the robot is designed to support 95 kg weight to include a 20 kg payload that can be carried by the robot arms having very light designs (with weight 8.5 kg), but each capable of carrying a 10 kg payload.An analysis of the closed-chain joint actuation systems of a light arm capable of handling heavy objects is performed, and the light arm is designed via finite-element method analysis performed using ANSYS. In addition, the kinematic analysis and the detailed structure of the arm and leg of the robot are performed.The main controller uses the ARM processor and a distributed controller for the leg joints is developed using the TMS320c2407 processor with the communications between the main and joint controllers being performed via the CAN system.Good performances of the proposed robot is demonstrated by presenting several experimental results; these include (1) experimentally handling a 13 kg payload, (2) through walking experiments of the robot supporting a 85 kg load, and (3) measurements of the arm and leg joint motors while performing walking experiments.

Robotica ◽  
2005 ◽  
Vol 24 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Hyeung-Sik Choi ◽  
Yong-Heon Park

We developed a new type of a human-sized BWR (biped walking robot) driven by the closed-chain type of a joint actuator. Each leg of the BWR is composed of three pitch joints and one roll joint. In all, a 12 degree-of-freedom robot, including four arm joints, was developed. The BWR was designed to walk autonomously; it is actuated by small 90W DC motors/drivers and is has DC batteries and controllers. A new type of the joint actuator for the BWR is composed of the four-bar-link mechanism driven by a ball screw which has high strength and high gear ratio despite its light weight.In this paper, analyses on the four-bar-link mechanism applied to the joint actuator and on the structure of the BWR are presented. Through walking experiments of the BWR, the superior trajectory-tracking ability of the proposed joint actuator is validated.


Aerospace ◽  
2004 ◽  
Author(s):  
Tian-Bing Xu ◽  
Ji Su

An electroactive polymer-ceramic hybrid actuation system (HYBAS) was recently developed. The HYBAS demonstrates significantly-enhanced electromechanical performance by utilizing advantages of cooperative contributions of the electromechanical responses of an electrostrictive copolymer and an electroactive single crystal. The hybrid actuation system provides not only a new type of device but also a concept to utilize different electroactive materials in a cooperative and efficient method for optimized electromechanical performance. In order to develop an effective procedure to optimize the performance of a hybrid actuation system (HYBAS), a theoretical model has been developed, based on the elastic and electromechanical properties of the materials utilized in the system and on the configuration of the device. The model also evaluates performance optimization as a function of geometric parameters, including the length of the HYBAS and the thickness ratios of the constituent components. The comparison between the model and the experimental results shows a good agreement and validates the model as an effective method for the further development of high performance actuating devices or systems for various applications.


Author(s):  
Ümit Yerlikaya ◽  
R. Tuna Balkan

Electromechanical actuators are widely used in miscellaneous applications in engineering such as aircrafts, missiles, etc. due to their momentary overdrive capability, long-term storability, and low quiescent power/low maintenance characteristics. This work focuses on electromechanical control actuation systems (CAS) that are composed of a brushless direct current motor, ball screw, and lever mechanism. In this type of CAS, nonlinearity and asymmetry occur due to the lever mechanism itself, saturation limits, Coulomb friction, backlash, and initial mounting position of lever mechanism. In this study, both nonlinear and linear mathematical models are obtained using governing equations of motion. By using the linear model, it is shown that employing a PI-controller for position and a P-controller for velocity will be sufficient to satisfy performance requirements in the inner-loop control of an electromechanical CAS. The unknown controller parameters and anti-windup coefficient are obtained by the Optimization Tools of MATLAB using nonlinear model. Results obtained from the nonlinear model and real-time unloaded and loaded tests on a prototype developed are compared to verify the nonlinear model.


Author(s):  
Fengyu Liu ◽  
Li Chen ◽  
Jian Yao ◽  
Chunhao Lee ◽  
Chi-kuan Kao ◽  
...  

Clutch-to-clutch shift technology is a key enabler for fast and smooth gear shift process for multi gear transmissions. However, conventional hydraulic actuation systems for clutches have drawbacks of low efficiency, oil leakage and inadequate robustness. Electromechanical devices offer potential alternative actuators. In this paper, a novel motor driven wedge-based clutch actuator, featuring self-reinforcement, is proposed. The design concept and physical structure are thoroughly described. Dynamic models for the actuation system and vehicle powertrain are validated by experiments. Upshift and downshift processes at different engine throttle openings, clutch clearances and friction coefficients are discussed. The results show that, the self-reinforcement ratio is tested as 9.6; at the same time, the shift quality is comparable to that of the conventional hydraulic actuated clutch in automatic transmissions in terms of the shift duration (about 1 s) and vehicle jerk (<10 m/s3). Taking advantage of fast response of the actuation DC motor, the wedge-based actuator is robust dealing with uncertain clutch clearance and friction coefficient. Therefore, the wedge-based clutch actuator has potential to provide acceptable performance for clutch-to-clutch shift.


Author(s):  
Rajiv Chaudhary ◽  
◽  
Alok Kumar Singh

Tracking the path of development in different Engineering disciplines, it can be easily observed that, right from the primitive stage, several tools, devices, and techniques may be identified, which happened by virtue of the evolution of human intelligence, getting transformed into various engineering applications. Although, later different engineering disciplines evolved, where most of the exhaustive development could be undertaken in that discipline. Likewise, in the field of mechanical engineering to various types of mechanical systems, according to the requirement in that field, were developed, in order to provide support of mechanization. Prime movers used to be an important part of these mechanical systems, which provided energy input as well as actuation required for providing the machines the desired kinematics. Most of the mechanical systems developed has been operated by conventional engine system using one or other fuel. Apart from the actuation by mechanical means, there are other means also through which mechanical actuation with better control, flexibility, and manipulation may be utilized in mechanical systems. A different category of systems, called Mechatronic systems has been developed in the recent past, which involves the vivid scope of use of techniques, devices, and components generally used in various other engineering fields of electrical, electronics, hydraulics, and pneumatics, etc. Subsequently, there have been several inventions, design & development which have added new levels in every field. Mechanical systems have been generally composed of various mechanical elements, which are designed to follow certain kinematics. The performance of the Actuation system plays an important role in the overall performance of the mechanical systems. There are several alternative actuation systems, which are not mechanical. These actuation systems may be categorized into electrical, electronics, hydraulic and pneumatic types. The features of these actuation systems, are so peculiar, that typical kinematic movement may be manipulated that too with more precision. Better control of mechanical systems may be realized, which is otherwise difficult with mechanical systems. In this paper, an effort has been made to review the possibilities, prospects as well as scope with various actuation systems.


2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987566
Author(s):  
Hanwen Yu ◽  
Xianying Feng ◽  
Qun Sun

This article presents a new micro-feed mechanism, whose main transmission component is the nut–rotary ball screw pair. The screw and nut are driven by two motors, and they rotate in the same direction, with their movements enabling micro-feeding. The main contribution of the micro-feed mechanism is to avoid the inevitable low-speed nonlinear creeping phenomenon caused by the inherent properties of traditional electromechanical servo system structure, thus realizing high precision micro-feed. In this study, the motion state of the working ball is analyzed using the principle of differential geometry, the friction at the contact points is calculated, the balance equation for force and moment is established, the influences of the screw and nut on the kinematic parameters of the ball at different velocities and the differences in the motion states of the ball in different drive modes are studied, and the mechanical efficiency of the dual-driven ball screw mechanism is calculated. The potential applications of the new micro-feed mechanism and the results of numerical analysis can be applied to advanced technology fields such as robotics, suspensions, powertrain, national defense, integrated electronics, optoelectronics, medicine, and genetic engineering, so that the new system can have a lower stable speed limit and achieve precise micro-feed control.


2013 ◽  
Vol 437 ◽  
pp. 382-387
Author(s):  
Guo Ping Zhao ◽  
Yuan Xun Fan ◽  
Feng Yang ◽  
Li Yi Li

Base on analyzing the design demand of the return system in the ball screws, combining the sine curve and the quintic parabola curve, this paper introduces a new type of curve for steel balls used in heavy load bearings. By computing and programming in Matlab, this paper gets the sine-quintic parabola curve and conducts the kinematic simulation based on it. The results show that the balls can get in and out of the return system continuously and cause low impulse force on the return system. The highest impulse force happens when the balls access the return system. All this results can contribute for the later design and research of the internal circulation return system.


2008 ◽  
Vol 1129 ◽  
Author(s):  
Alexandra Vanderhoff ◽  
Kwang Kim

AbstractThe study determines the feasibility of a new actuation system that couples a fluidic artificial muscle designed by Festo [1] with a metal hydride hydrogen compressor to create a compact, lightweight, noiseless system capable of high forces and smooth actuation. An initial model for the complete system is developed. The analysis is restricted in some aspects concerning the complexity of the hydriding/dehydriding chemical process of the system and the three-dimensional geometry of the reactor, but it provides a useful comparison to other actuation devices and clearly reveals the parameters necessary for optimization of the actuation system in future work. The system shows comparable work output and has the benefits of biological muscle-like properties [2] for use in robotic systems. When compared to other previously developed metal hydride actuation systems the potential for increasing the reaction kinetics and improving the overall power output of the system is revealed. A comparison of the system to common actuation devices, including a biological muscle, shows similar stress and strain relations, but a lower power and frequency range due to the slow actuation time. Improving the reaction kinetics of the system will be the first approach to enhancing the system, along with optimization of the mass and type of metal hydride used in the reactor to produce a full actuation stoke of the fluidic muscle while minimizing system weight.


Author(s):  
Shaju John ◽  
Jin-Hyeong Yoo ◽  
Norman M. Wereley

There is a demand for compact hybrid actuation systems which combines actuation and valving systems in a compact package. Such self-contained actuation systems have potential applications in the field of rotorcraft (as active pitch links) and automotive engineering (as active vibration control devices). Hybrid hydraulic actuation systems, based on frequency rectification of the high frequency motion of an active material, can be used to exploit the high bandwidth of smart material to design devices with high force and stroke. Magnetorheological (MR) fluids are active fluids whose viscosity can be changed through the application of a magnetic field. By using MR fluids as the hydraulic fluid in such hybrid devices, a valving system with no moving parts can be implemented. Such a system will be attractive in rotorcraft applications with large centrifugal force loading. Thus, MR fluids can be used to control the motion of an output cylinder. The MR fluid based valves can be configured in the form of a Wheatstone bridge to produce bi-directional motion in an output cylinder by alternately applying a magnetic field in the two arms of the bridge. In this study, the actuation is performed using a compact Terfenol-D stack driven actuator. The frequency rectification of the stack motion is done using reed valves. This actuator and valve configuration form a compact hydraulic system with fluidic valves. The advantages of such systems are that part count is low, absence of moving parts and the possibility of continuous controllability of the output cylinder. By applying varying magnetic fields in the arms of the bridge (by applying different currents to the coils), the differential pressure acting on the output cylinder can be controlled. The description of the experimental setup, the tests performed and the experimental results are presented in this paper.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zheng Ge ◽  
Weirui Wang

We propose the planetary flywheel inerter, which is a new type of ball screw inerter. A planetary flywheel consists of several planetary gears mounted on a flywheel bracket. When the flywheel bracket is driven by a screw and rotating, each planetary gear meshing with an outer ring gear generates a compound motion composed of revolution and rotation. Theoretical analysis shows that the output force of the planetary flywheel inerter is proportional to the relative acceleration of one terminal of the inerter to the other. Optimizing the gear ratio of the planetary gears to the ring gear allows the planetary flywheel to be lighter than its traditional counterpart, without any loss on the inertance. According to the structure of the planetary flywheel inerter, nonlinear factors of the inerter are analyzed, and a nonlinear dynamical model of the inerter is established. Then the parameters in the model are identified and the accuracy of the model is validated by experiment. Theoretical analysis and experimental data show that the dynamical characteristics of a planetary flywheel inerter and those of a traditional flywheel inerter are basically the same. It is concluded that a planetary flywheel can completely replace a traditional flywheel, making the inerter lighter.


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