这个问题与以下问题密切相关这个问题与“adding-forces-to-body-post-finalize”
我希望能够对 pydrake 中的简单几何图元施加外力。这是为了对机构之间的相互作用进行评估。
我当前的实现：
builder = DiagramBuilder()
plant = builder.AddSystem(MultibodyPlant(0.001))
parser = Parser(plant)
cube_instance = parser.AddModelFromFile('cube.urdf', model_name='cube')
plant.Finalize()
force = builder.AddSystem(ConstantVectorSource(np.zeros(6)))
builder.Connect(force.get_output_port(0), plant.get_applied_spatial_force_input_port())
diagram = builder.Build()
但是，当我运行它时，我收到以下错误：
builder.Connect(force.get_output_port(0), plant.get_applied_spatial_force_input_port())
RuntimeError: DiagramBuilder::Connect: Cannot mix vector-valued and abstract-valued ports while connecting output port y0 of System drake/systems/ConstantVectorSource@0000000002db5aa0 to input port applied_spatial_force of System drake/multibody/MultibodyPlant@0000000003118680
我倾向于实现一个 LeafSystem，它在工厂上实现抽象值端口。
使用：AbstractValue 和 ConstantValueSource
value = AbstractValue.Make([np.zeros(6)])
force = builder.AddSystem(ConstantValueSource(value))
ref_vector_externally_applied_spatial_force = plant.get_applied_spatial_force_input_port()
builder.Connect(force.get_output_port(0), ref_vector_externally_applied_spatial_force)
我收到以下错误：
RuntimeError: DiagramBuilder::Connect: Mismatched value types while connecting
output …drake ×1