Mars 2020 Robotic Operations is responsible for the development, planning and Mars execution of robotics aspects of the mission. This includes the Perseverance rover's mobility, manipulation, and ...sampling operations, and the Ingenuity helicopter's flights. As of October 2022 (Martian Solar Day 562, or sol 562), the rover has driven 13,179.5m and collected 15 samples, while the helicopter has logged 32 flights, covering 7281m, with an overall flight time of 3467 seconds. Perseverance and Ingenuity have accomplished several firsts such as coring and caching samples autonomously, and demonstrating powered flight on Mars. Perseverance has also set new planetary rover records such as the longest continuation drive distance (699.9m with no human review), longest single-sol autonomous drive distance (319m), and total autonomously evaluated drive distance (11,594m out of 13,172m total, i.e. 88% of all driving, an order of magnitude more than previous NASA Mars rover missions). This paper presents results from the first year and a half of Mars operations to highlight the operations approach that enabled this success, the challenges encountered, and lessons learned. Challenges include an unexpected reboot while driving that led to the discovery of a race condition in the rover flight software, pebbles unexpectedly interfering with key sampling hardware, the Martian winter temporarily grounding the helicopter, and difficult communication situations between the rover and he-licopter that arise during periods of limited mobility. This paper also describes the sampling sol path, which is used by the operations team to execute sampling activities in a repeatable manner consistent with the goals of the science team and the capabilities of the sampling hardware. Abrading and sampling performance to date is evaluated, with a particular emphasis on changes to operations as a result of the soft rocks encountered in the Delta region on the western border of Jezero Crater.
NASA’s Mars Exploration Rovers (MER) have collected a great diversity of geological science results, thanks in large part to their surface mobility capabilities. The six wheel rocker/bogie suspension ...provides driving capabilities in many distinct terrain types, the onboard IMU measures actual rover attitude changes (roll, pitch and yaw, but not position) quickly and accurately, and stereo camera pairs provide accurate position knowledge and/or terrain assessment. Solar panels generally provide enough power to drive the vehicle for at most four hours each day, but drive time is often restricted by other planned activities. Driving along slopes in nonhomogeneous terrain injects unpredictable amounts of slip into each drive. These restrictions led us to create driving strategies that maximize drive speed and distance, at the cost of increased complexity in the sequences of commands built by human Rover Planners each day.
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The Mars Science Laboratory (MSL) Curiosity rover experienced increasing wheel damage beginning in October 2013. While the wheels were designed to operate with considerable damage, the rate at which ...damage was occurring was unexpected and raised concerns regarding wheel lifetime. The Jet Propulsion Laboratory (JPL) has now developed and deployed new software on Curiosity that reduces the forces acting on the wheels. Our new Traction Control algorithm adapts each wheel's speed to fit the terrain it drives over. It does not rely on any a priori knowledge of the terrain, and instead leverages the rover's measured attitude rates and suspension angles, together with a rigid-body kinematics model, to estimate the real-time wheel-terrain contact angles and ideal, no-slip wheel angular rates. In addition, free-floating "wheelies" are detected and autonomously corrected. In this paper, we describe the algorithm, its ground testing campaign and associated challenges, and finally its validation and performance in flight. Ground test data demonstrates reductions in the forces acting on the wheels and validates the wheelie-damping capability. Secondary benefits in some terrains include a reduction in heading deviations while climbing rocks, with a reduction in slip in certain sandy terrains. Preliminary validation from flight data confirms these findings.
This paper includes a summary, lessons learned, and upcoming plans from the first 210 Mars solar days (sols) of NASA's Mars 2020 Perseverance rover mission. The focus of the paper is on Robotic ...Operations, which is the team with the primary responsibility for strategic planning, uplink commanding and downlink analysis for rover mobility and navigation, robotic arm operation, the sampling and caching capability including coring, the adaptive caching assembly and the 2nd sample handling robotic arm, and the interface to the Mars helicopter Ingenuity. As of Sol 210 the rover has driven 2663.65 meters, executed 20764 robotic arm and sampling commands, and has successfully completed 13 helicopter flights covering 2382 meters horizontal distance. It includes Operations Readiness Tests executed in preparation for landing, landing and initial checkouts, strategic route planning to the science destination and waypoints, and surface checkout of all of the robotics capabilities of the rover. It also discusses the strategic planning and tactical agility needed to interleave science investigations and the technology demonstration of the Mars helicopter flights where a minimum distance had to be maintained between the rover and helicopter during flights. It discusses the challenges with planning robotic operations and addressing anomalies with the larger uncertainty present during early mission operations. It also discusses the impact on robotic operations from lessons incorporated from previous missions.
The CPU Utilization Statistics Plotter (CUSP) tool automates the interpretation of detailed CPU Utilization trace data and statistics. It puts you on the cusp of understanding how CPU resources are ...split among the many parallel components of a software system. CUSP combines time-sampled CPU utilization numbers and Event Log annotations to generate human-readable plots and tables. It automatically splits up large CPU usage log files around interesting events, determines and highlights just the tasks of primary relevance by evaluating their changing contribution to each plot's total CPU usage, automatically eliminates irrelevant tasks, provides context by labeling plots with names and durations of all active commands, and uses consistent color-coding to enable quick visual comparison across multiple plots. CUSP has been used to process CPU Utilization trace logs on the Mars Science Laboratory and the Mars 2020 Rover missions during flight software development and Flight Operations on the Martian surface since December 2013.
NASA's Mars exploration rovers' (MER) onboard mobility flight software was designed to provide robust and flexible operation. The MER vehicles can be commanded directly, or given autonomous control ...over multiple aspects of mobility: which motions to drive, measurement of actual motion, terrain interpretation, even the selection of targets of interest (although this mode remains largely underused). Vehicle motion can be commanded using multiple layers of control: motor control, direct drive operations (arc, turn in place), and goal-based driving (goto waypoint). Multiple layers of safety checks ensure vehicle performance: command limits (command timeout, time of day limit, software enable, activity constraints), reactive checks (e.g., motor current limit, vehicle tilt limit), and predictive checks (e.g., step, tilt, roughness hazards). From January 2004 through October 2005, Spirit accumulated over 5000 meters and Opportunity 6000 meters of odometry, often covering more than 100 meters in a single day. In this paper we describe the software that has driven these rovers more than a combined 11,000 meters over the Martian surface, including its design and implementation, and summarize current mobility performance results from Mars
Since landing on the Meridiani Planum region of Mars in January 2004, the Mars exploration rover (MER) vehicle named Opportunity has been sending back pictures taken from several different craters ...that would provide evidence that the region did indeed have a watery past. This paper details the experience of driving Opportunity through this alien landscape during its first 400 days on Mars, from the point of view of the other rover planners, the people who tell the rover where to drive and how to use its robotic arm
Over the first 9 years of the Mars Science Laboratory (MSL) Curiosity rover's surface mission, more than 87% of its driving was performed using Visual Odometry (VO). The benefits of using VO during ...driving are that it minimizes rover position uncertainty and can be used to monitor wheel slip, halting a drive if excessive wheel slip is occurring. The VO implementation onboard Curiosity acquires and processes VO images in between drive steps while the rover is stationary. A VO Thinking While Driving (VTWD) flight software capability has been developed to enable the processing of VO images during rover driving, increasing the distance Curiosity can drive using VO during a given time period up to as much as 1.75x total distance. Verification and Validation (V&V) of this capability has been challenging due to impacts from the COVID-19 pandemic and unavailability of the JPL Mars Yard outdoor test site. The VTWD V&Vtest procedures were modified to use a small indoor space with Mars-like terrain. This paper describes the 3 year V&V effort under challenging conditions to approve the VTWD capability for use on the Curiosity rover.
