scholarly journals Design of Direct-Drive Mechanical Arms

1983 ◽  
Vol 105 (3) ◽  
pp. 312-316 ◽  
Author(s):  
Haruhiko Asada ◽  
Takeo Kanade
Keyword(s):  
Rare Earth ◽  
High Speed ◽  
Design Theory ◽  
High Reliability ◽  
Kinematic Model ◽  
Light Weight ◽  
Direct Drive ◽  
Mass System ◽  
Compact Size ◽  
High Torque

This paper describes the design concept of a new robot based on the direct-drive method using rare-earth d-c torque motors. Because these motors have high torque, light weight and compact size, we can construct robots with far better performance than those presently available. For example, we can eliminate all the transmission mechanisms, such as reducers and chain belts, between the motors and their loads, and construct a simple mechanism (direct-drive) where the arm links are directly coupled to the motor rotors. This elimination can lead to excellent performance: no backlash, low friction, low inertia, low compliance and high reliability, all of which are suited for high-speed, high-precision robots. First we propose a basic configuration of direct-drive robots. Second a general procedure for designing direct-drive robots is shown, and the feasibility of direct drive for robot actuation is discussed in terms of weights and torques of joints. One of the difficulties in designing direct-drive robots is that motors to drive wrist joints are loads for motors to drive elbow joints, and they are loads for motors at shoulders. To reduce this increasing series of loads is an essential issue for designing practical robots. We analyze the joint mass system for simplified kinematic model of the direct-drive robots, and show how the loads are reduced significantly by using rare-earth motors with light-weight and high torque. We also discuss optimum kinematic structures with minimum arm weight. Finally, we describe the direct-drive robotic manipulator (CMU arm) developed at Carnegie-Mellon University, and verify the design theory.

Design of a Kind of Novel Limited-Angle Brushless Torque Motor

2012 ◽  
Vol 468-471 ◽  
pp. 871-874 ◽  
Author(s):  
Zhan Ting Fan ◽  
Wei Guo Liu ◽  
An Chao He
Keyword(s):  
Automatic Control ◽  
High Reliability ◽  
Basic Structure ◽  
Electromagnetic Torque ◽  
Test Results ◽  
Direct Drive ◽  
Electrical Drive ◽  
Welding Equipment ◽  
High Torque ◽  
Limited Angle

A kind of 5Nm prototype LABLTM (Limited-Angle Brushless Torque Motor) is presented and designed. The basic structure of the motor is deliberated. The method of calculating the electromagnetic torque is provided. The Magnet software is used to optimize some important parameters of the motor. The prototype is fabricated. The test results of the prototype indicate that the LABLTM, with high torque and high reliability, does meet the requirements of direct drive actuator of precision welding equipment. It has a promising future in automatic control, electrical drive, etc.

scholarly journals Investigation of a New Flux-Modulated Permanent Magnet Brushless Motor for EVs

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Fan ◽  
Lingling Gu ◽  
Yong Luo ◽  
Xuedong Han ◽  
Ming Cheng
Keyword(s):  
High Speed ◽  
Simple Structure ◽  
Static Characteristics ◽  
Direct Drive ◽  
Element Analysis ◽  
Torque Density ◽  
Brushless Motor ◽  
Design Requirements ◽  
High Torque ◽  
Compact Design

This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation.

scholarly journals Design and Experimental Validation for Direct-Drive Fault-Tolerant Permanent-Magnet Vernier Machines

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Guohai Liu ◽  
Junqin Yang ◽  
Ming Chen ◽  
Qian Chen
Keyword(s):  
Permanent Magnet ◽  
Experimental Validation ◽  
Fault Tolerant ◽  
Design Method ◽  
High Reliability ◽  
Direct Drive ◽  
Torque Density ◽  
Time Stepping ◽  
Flux Modulation ◽  
High Torque

A fault-tolerant permanent-magnet vernier (FT-PMV) machine is designed for direct-drive applications, incorporating the merits of high torque density and high reliability. Based on the so-called magnetic gearing effect, PMV machines have the ability of high torque density by introducing the flux-modulation poles (FMPs). This paper investigates the fault-tolerant characteristic of PMV machines and provides a design method, which is able to not only meet the fault-tolerant requirements but also keep the ability of high torque density. The operation principle of the proposed machine has been analyzed. The design process and optimization are presented specifically, such as the combination of slots and poles, the winding distribution, and the dimensions of PMs and teeth. By using the time-stepping finite element method (TS-FEM), the machine performances are evaluated. Finally, the FT-PMV machine is manufactured, and the experimental results are presented to validate the theoretical analysis.

scholarly journals Design of a Quasi-Direct-Drive Actuator for Dynamic Motions

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 11
Author(s):  
Akash Singh ◽  
Navvab Kashiri ◽  
Nikolaos Tsagarakis
Keyword(s):  
High Speed ◽  
Mechanical Design ◽  
Torque Control ◽  
Direct Drive ◽  
Torque Density ◽  
Planetary Gearbox ◽  
High Torque ◽  
And Performance ◽  
The Stability ◽  
Joint Motions

In recent years, several legged/wheeled robots have been developed, and their effective functionality in locomotion on uneven terrains has been proved. Many robotics researchers have been focusing on improving the locomotion speed as well as the stability and robustness of such robots. High-speed locomotion of robots is, however, subject to various design challenges, especially in the development of actuators. The robotic applications that require high-speed motion in high-torque operations along with the ability to manage dynamic physical interactions are not satisfied by the conventional robotic actuators deploying high-reduction gearings. In this work, we present a quasi-direct-drive actuator designed for continuous high-speed motions in high torque, such as wheeled motions in mobile robots or joint motions in dynamic-legged robots. The presented actuator exploits low-reduction gearing so that it can render over 26 Nm of continuous torque, while the actuator speed can exceed 37 rad/s. Such characteristics enable the exhibition of dynamic motions and can deal with large external impacts. The selection of the motor and design of the gearing unit was carried out iteratively so that commercial items with minimum customization could be employed and the outer diameters of the motor and the gearbox could match. A single-level planetary gearbox was devised for the reduction unit to ensure high back-drivability and transparency of the actuator, thereby making the actuator robust against external impacts and allowing for accurate torque control using motor current measurement. The gear set design was carried out based on the AGMA gear torque calculation. Given the radial space required for the gearbox to deal with the torque requirements, the actuator motor was chosen to be small in height (pancake type), which ensures high torque density within smaller dimensions at high-speed operation. The mechanical design of the actuator is presented in this paper, and the actuator’s specifications in terms of size and performance are compared with those of similar state-of-the-art actuators.

The Application and Development of the High Speed Overrunning Clutch in the Transmission System of the Helicopter

2011 ◽  
Vol 86 ◽  
pp. 283-286
Author(s):  
Yan Ying Jiang ◽  
Zhen Rong Yang ◽  
Jie Gao
Keyword(s):  
Power System ◽  
High Speed ◽  
High Reliability ◽  
Transmission System ◽  
Rotor System ◽  
Light Weight ◽  
Design Characteristic ◽  
Long Life ◽  
Critical Components

The overrunning clutch is one of the critical components that can engage and disengage according to the movement requirement of the power system and the rotor system. The merits of the different overrunning clutch are analyzed by the design characteristic, reliability, weight, process of the manufacture and so on. In the end, the application and development of the high speed overrunning clutch are discussed according to the characteristics of the transmission system that have high reliability, long life and light weight.

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

scholarly journals Production of Porous Ceramic Materials from Spent Fluorescent Lamps

2021 ◽  
Vol 11 (13) ◽  
pp. 6056
Author(s):  
Egle Rosson ◽  
Acacio Rincón Rincón Romero ◽  
Denis Badocco ◽  
Federico Zorzi ◽  
Paolo Sgarbossa ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
High Speed ◽  
Porous Ceramic ◽  
Ceramic Materials ◽  
Porous Ceramics ◽  
Fluorescent Lamps ◽  
Naoh Solution ◽  
Commercial Glass ◽  
Triton X

Spent fluorescent lamps (SFL) are classified as hazardous materials in the European Waste Catalogue, which includes residues from various hi-tech devices. The most common end-of-life treatment of SFL consists in the recovery of rare earth elements from the phosphor powders, with associated problems in the management of the glass residues, which are usually landfilled. This study involves the manufacturing of porous ceramics from both the coarse glass-rich fraction and the phosphor-enriched fraction of spent fluorescent lamps. These porous materials, realizing the immobilization of Rare Earth Elements (REEs) within a glass matrix, are suggested for application in buildings as thermal and acoustic insulators. The proposed process is characterized by: (i) alkaline activation (2.5 M or 1 M NaOH aqueous solution); (ii) pre-curing at 75 °C; (iii) the addition of a surfactant (Triton X-100) for foaming at high-speed stirring; (iv) curing at 45 °C; (v) viscous flow sintering at 700 °C. All the final porous ceramics present a limited metal leaching and, in particular, the coarse glass fraction activated with 2.5 M NaOH solution leads to materials comparable to commercial glass foams in terms of mechanical properties.

scholarly journals Observation and analysis of diving beetle movements while swimming

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debo Qi ◽  
Chengchun Zhang ◽  
Jingwei He ◽  
Yongli Yue ◽  
Jing Wang ◽  
...  
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Kinematic Model ◽  
Movement Pattern ◽  
Unmanned Vehicles ◽  
Power Stroke ◽  
Cross Sectional ◽  
Motion Data ◽  
The Cross ◽  
Diving Beetle

AbstractThe fast swimming speed, flexible cornering, and high propulsion efficiency of diving beetles are primarily achieved by their two powerful hind legs. Unlike other aquatic organisms, such as turtle, jellyfish, fish and frog et al., the diving beetle could complete retreating motion without turning around, and the turning radius is small for this kind of propulsion mode. However, most bionic vehicles have not contained these advantages, the study about this propulsion method is useful for the design of bionic robots. In this paper, the swimming videos of the diving beetle, including forwarding, turning and retreating, were captured by two synchronized high-speed cameras, and were analyzed via SIMI Motion. The analysis results revealed that the swimming speed initially increased quickly to a maximum at 60% of the power stroke, and then decreased. During the power stroke, the diving beetle stretched its tibias and tarsi, the bristles on both sides of which were shaped like paddles, to maximize the cross-sectional areas against the water to achieve the maximum thrust. During the recovery stroke, the diving beetle rotated its tarsi and folded the bristles to minimize the cross-sectional areas to reduce the drag force. For one turning motion (turn right about 90 degrees), it takes only one motion cycle for the diving beetle to complete it. During the retreating motion, the average acceleration was close to 9.8 m/s2 in the first 25 ms. Finally, based on the diving beetle's hind-leg movement pattern, a kinematic model was constructed, and according to this model and the motion data of the joint angles, the motion trajectories of the hind legs were obtained by using MATLAB. Since the advantages of this propulsion method, it may become a new bionic propulsion method, and the motion data and kinematic model of the hind legs will be helpful in the design of bionic underwater unmanned vehicles.

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