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In complex terrain exploration and narrow-space inspection tasks, chassis maneuverability often determines the success or failure of a mission. In this video, we showcase the highly representative Legacy V2 four-wheel independent steering exploration vehicle.
The chassis adopts an innovative 4WS4WD (Four-Wheel Steering and Four-Wheel Drive) architecture and integrates CubeMars AK Series actuator modules as the core power and motion control units. It successfully achieves omnidirectional mobility capabilities, including zero-radius in-place rotation and lateral translation, providing extreme flexibility for specialized exploration applications.
Traditional mobile robot chassis designs, such as Ackermann steering, skid steering, and conventional differential drive systems, perform well in open environments. However, when facing narrow corridors, dense pipelines, or complex ruins, they often reveal significant limitations:
Large Turning Radius: Traditional chassis systems cannot easily perform U-turns or posture adjustments in confined spaces, making them prone to getting stuck or colliding with obstacles.
Lack of Lateral Movement Capability: Conventional chassis cannot directly move sideways. When precise positioning is required, such as docking with a hatch or approaching an inspection point, multiple reversing and repositioning operations are often needed, reducing efficiency.
High Difficulty in Multi-Axis Coordinated Control: To achieve true omnidirectional movement, each wheel must independently support both driving and steering functions. This places extremely high demands on motor response speed and synchronization accuracy.
To overcome these physical limitations, the Legacy V2 development team equipped each wheel module with CubeMars AK Series motors, creating a highly flexible four-wheel independent steering system.
Its key advantages in the system include:
High Power Density for Perfect Wheel Module Integration: Four-wheel independent steering means that each wheel module must contain both driving and steering mechanisms, making the available installation space extremely limited. CubeMars AK motors integrate the brushless motor, reduction mechanism, and driver into a highly compact unit while maintaining strong torque output. This high power density design allows the motors to be easily embedded into wheel modules without significantly increasing unsprung mass, ensuring excellent vehicle mobility and terrain adaptability.
Precise Position and Speed Control for Multi-Axis Synchronization: The core algorithm behind omnidirectional movement, such as lateral crab walking and in-place rotation, relies on kinematic calculations. However, the key to physical implementation is that the steering angles and driving speeds of all four wheels must remain precisely synchronized. CubeMars motors feature built-in high-resolution encoders, support high-frequency CAN bus communication, and utilize FOC control algorithms. They can accurately execute position and speed commands from the upper-level controller with extremely low latency, ensuring smooth and stable execution of complex motion trajectories.
Strong Off-Road Capability and Load Performance: As an exploration vehicle, the chassis must not only “move intelligently” but also “move reliably.” The AK Series motors provide excellent overload capability and impact resistance. Even in unstructured environments such as muddy terrain, gravel surfaces, and other challenging conditions, they can continuously deliver stable and reliable power output for the four-wheel independent steering system.
In this video, you can directly observe the advanced maneuverability of the Legacy V2 exploration vehicle powered by CubeMars motors:
Lateral Translation (Crab Walking Mode)
All four wheels rotate to the same steering angle, allowing the chassis to move sideways directly into narrow passages without changing the vehicle’s forward-facing direction.
Zero-Radius In-Place Rotation: The four wheels rotate to centrally symmetrical steering angles, enabling the vehicle body to rotate precisely around its center like a gyroscope, easily handling dead-end turns and confined spaces.
Diagonal Driving and Flexible Obstacle Avoidance: The chassis dynamically adjusts each wheel’s steering angle to navigate through complex obstacles using optimized movement paths.
Q1: What special requirements do motors need to meet for developing a four-wheel independent steering (4WS) chassis?
A: The biggest challenge lies in the decoupling and coordination between steering and driving.
The motors need to provide:
Extremely fast dynamic response
Precise closed-loop position control
High-frequency communication interfaces (such as CAN FD or high-speed CAN)
This ensures that the lower-level actuators do not become a latency bottleneck when the chassis controller performs complex kinematic calculations.
The CubeMars AK Series is specifically designed for advanced chassis control applications like these.
Q2: What commercial or research applications are suitable for this type of omnidirectional mobile chassis?
A: It is highly suitable for scenarios requiring exceptional maneuverability in limited spaces, including:
Inspection robots for narrow environments such as pipelines, ship cabins, and warehouse shelving areas
Specialized disaster rescue exploration vehicles
Agricultural orchard harvesting platforms
Multi-axis vehicle dynamics research and validation platforms for universities and research institutions
Whether it is a four-wheel independent steering exploration vehicle, a Mecanum wheel AGV, or a complex specialized robotic platform, CubeMars provides highly integrated and fast-response miniature drive solutions.
[Learn more about CubeMars AK Series actuator modules]
