Suspension
worldThe rover utilizes a passive rocker-bogie suspension architecture coupled with a top-mounted differential rocker mechanism. This mechanical design allows all six wheels to maintain continuous contact with uneven terrain without relying on active electronic stabilization or heavy spring-damper assemblies.
System Architecture & Components
The suspension relies on purely kinematic links to distribute weight evenly and isolate the central payload chassis from violent pitching when traversing obstacles.
- Rocker-Bogie Side Linkages: Two independent side linkages (left and right). Each main rocker pivots relative to the chassis, while the rear bogie links pivot relative to the main rocker, allowing the wheels to contour over rocks and dips.
- Chassis Pivot Mounting Assemblies:
- Located on the left and right side plates of the chassis frame to serve as the primary structural attachment points for the main rockers.
- Utilize heavy-duty pivot axles supported by dual radial ball bearings (or flange bearings) to isolate bending moments caused by lateral wheel forces.
- Feature reinforced structural backing plates inside the chassis to distribute point loads across the frame walls and prevent localized chassis flexing.
- Top-Mounted Differential Rocker Arm:
- A rigid cross-bar mounted horizontally over the top deck of the chassis, rotating around a central vertical plane pivot pin.
- Connects the left and right main rocker arms using vertical tie-rods (turnbuckles) with spherical rod ends (heim joints).
- Enforces anti-phase motion between the left and right suspension sides: as one side lifts over an obstacle, the top rocker pivots and forces the opposite side downward.
Design Rationale & Kinematic Mechanics
Why a Passive Rocker-Bogie with a Top Differential Bar?
- 1. Equalized Wheel Loading & Traction: In conventional spring suspension systems, climbing a large step severely compresses one corner, shifting the vehicle's center of mass and reducing ground pressure on the remaining wheels. The passive rocker-bogie geometry mechanically balances vertical loads so that all six wheels share traction equally, minimizing wheel slip on loose terrain.
- 2. Chassis Pitch Averaging (Differential Kinematics): Without a differential linkage, the chassis body would freely tilt to extreme angles whenever a single side encountered an obstacle. The top-mounted differential arm acts as a mechanical motion-averaging box. If the left rocker rotates 10° over a rock, the top bar forces the right side down, holding the body deck at a stable pitch. Positioned over the top deck, the bar keeps the underside of the chassis completely clear of cross-axles, maintaining maximum ground clearance.
- 3. Direct Chassis Mount Considerations: Heavy impact forces from the suspension flow directly into the chassis side plates through the primary pivot mounts. Placing high-capacity bearings at these specific mounting points prevents binding under side-loading (e.g., when turning on a steep slope) while preserving smooth pitch rotation during obstacle negotiation.