| With the increased importance of actuator performance in robotic applications, many robot manufacturers have focused on assuring quality, reliability, conformance to design, and application suitability in their actuators. Performance metrics for actuator evaluation have been proposed to improve understanding of an actuator's nonlinear characteristics. Thorough actuator testing can provide necessary feedback information on the effectiveness of the robot actuator for a specific task. This report describes the development and use of performance maps and performance envelopes for electromechanical actuators using an advanced dynamic dynamometer test bed. Initial test data in the form of performance maps is created for a range of rated output power and dynamic loading for brushless DC motors.; The core contributions of this research are the creation and manipulation of actuator performance maps and envelopes, and the design and development of a nonlinear test bed for electromechanical actuators. To create a performance map, specific criteria must be developed to describe the performance characteristics of an actuator. The performance criteria are formulated to define, anticipate, and evaluate the performance responses of the system and can provide metrics for measuring and controlling actuator performance and help identify nonlinear components in actuator modeling. These criteria form the basis for performance maps, which is basically a data representation of the criteria over a range of input and output conditions. A representative set of ten actuator performance maps are suggested based on several independent control parameters such as current and voltage, and output conditions such as torque and speed. After completing the development and analysis of these ten performance maps, the process for building unique performance envelopes is described. Performance envelopes are created from performance maps and are defined as the combined optimum surface in the full set of maps, which satisfy a combination of criteria in each operational region. Performance envelopes can safely increase the number of control surfaces without violating actuator constraints. This provides more choices in an operational range as compared to statically developed torque-speed curves.; For the creation of these performance maps, five test regimes are suggested such as dynamic loading, static loading, transient response, torque ripple and statically changing temperature tests. Test regimes are evaluated under two types of loads: a static loading and a sinusoidal loading. For these test protocols, a Nonlinear Test Bed for Actuators (NTBA) has been designed and built to measure and record an array of physical performance properties. (Abstract shortened by UMI.)... |
