Significance and Use
5.1 Traversing on terrains with small aggregate (such as Number 8 or smaller gravel, per Specification C33/C33M) could pose problems for ground robots because the aggregate may become incrementally packed into the locomotion subsystems (such as driving sprockets, belts, chains, tire treads, or track pads) leading to jamming, slippage, or other failures, and thus adversely affecting a robot’s mobility. This test method addresses aforementioned issues of mobility.
Note 1: Larger-sized gravel might not be as easily packed into robotic locomotion subsystems but might present different types of mobility challenges such as angular, rough, sharp, or broken aggregate pieces interfering with wheels, tracks, or other types of locomotion mechanisms. These issues are out of the scope of this test method.
5.1.1 Small gravel based terrains are non-rigid in nature and could cause a robot to turn-in-place or dig-in when the robot is negotiating a tight turn. Certain robotic locomotion mechanisms might be designed for other mobility purposes and might not create sufficient traction against the specified gravel terrain. As such, extensive testing within this type of terrain may expose robot design or reliability issues and lead to field maintenance or repair.
5.1.2 The gravel traverse capabilities could be affected by additional factors such as the weight and its distribution, ground contact areas, and control schemes for the robot. As such, extensive testing within this type of terrain may also lead to innovations in robot design.
5.2 Key features of response robots are that they are remotely operated from safe standoff distances, deployable at operational tempos, capable of operating in complex environments, sufficiently hardened against harsh environments, reliable and field serviceable, durable or cost-effectively disposable, and equipped with operational safeguards. As such, a major advantage of using robots in response operations is to enhance the safety and effectiveness of responders or soldiers.
5.3 This test method aligns user expectations with actual capabilities to understand the inherent capability trade-offs in deployable systems at any given cost. For example, a design issue of the number of batteries to be packed on a robot could affect desired weight, endurance, or cost. Appropriate levels of understanding can help ensure that requirement specifications are articulated within the limit of current capabilities.
5.4 This test method provides a tangible representation of essential robot capabilities with quantifiable measures of performance. When considered with other related test methods in the suite, it facilitates communication among communities of robot users and manufacturers. As such, this test method can be used to:
5.4.1 Inspire technical innovation and guide manufacturers toward implementing combinations of capabilities necessary to perform essential mission tasks.
5.4.2 Measure and compare essential robot capabilities. This test method can establish the reliability of the system to perform specified tasks, highlight break-through capabilities, and encourage hardening of developmental systems.
5.4.3 Inform purchasing decisions, conduct acceptance testing, and align deployment objectives with statistically significant robot capabilities data captured through repeated testing and comparison of quantitative results.
5.4.4 Focus operator training and measure proficiency as a repeatable practice task that exercises actuators, sensors, and operator interfaces. The test method can be embedded into training scenarios to capture and compare quantitative scores even within uncontrolled environmental variables. This can help develop, maintain, measure, and track very perishable skills over time and enable comparisons across squads, regions, or national averages.
5.5 Although this test method was developed for response robots, it may be applicable to other domains. Different user communities can set their own thresholds of acceptable performance within the test method for various mission requirements.
5.6 It is recommended that users of this test method consider their particular robot requirements when interpreting the test results. The capability evaluated in this test method alone shall be interpreted according to the scope of this test method and shall not be considered as an overall indication of the capability of the robot’s mobility system nor of the entire robotic system. A single test method only captures the specified single aspect of a robot’s capabilities. A more complete characterization of a robot’s capabilities requires test results from a wider set of test methods.
Scope
1.1 The purpose of this test method is to specify the apparatuses, procedures, and performance metrics necessary to quantitatively measure a teleoperated ground robot’s capability of traversing gravel terrain. The primary performance metric for this test method shall be a robot’s possession of such a capability with a specified statistical significance level.
1.2 Average rate of advance over the specified terrain shall be the secondary performance metric for this test method. The measure shall be calculated only when a robot under test has completed a statistically-significant number of repetitions.
1.3 This test method can also be used to measure the operator proficiency in performing the specified task. The corresponding performance metric may be the number of completed task repetitions per minute over an assigned time period ranging from 10 to 30 minutes.
1.4 This test method is a part of the mobility suite of ground response robot test methods, but this test method is stand-alone and complete. This test method applies to ground systems operated remotely from a standoff distance appropriate for the intended mission. The system includes a remote operator in control of all functionality and any assistive features or autonomous behaviors that improve the effectiveness or efficiency of the overall system.
1.5 The apparatus, specified in Section 6, can only test a limited range of a robot’s capabilities. When the robot has been tested through the limit or limits of the apparatus, a note shall be associated with the results indicating that the robot’s actual capability may be outside of the limit or limits imposed by the test apparatus. For example, the size of the gravel terrain test apparatus could possibly affect the acceleration of the robot under test and, in turn, the resulting average rate of advance.
1.6 Performing Location—This test method may be performed anywhere the specified apparatuses and environmental conditions can be implemented.
1.7 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. Both units are referenced to facilitate acquisition of materials internationally and minimize fabrication costs.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
