111
Development of a Low-Noise Bio-Inspired Humanoid Robot Neck
sealed in the sound insulation box, and (3) the drive system is dominated by
the low-friction and highly efficient cable-and-housing group, the humanoid
head/neck system can mimic well the motion of a human head without generating unacceptable motion noises.
6.2.3 Programming Head Movements
The 3-DOF neck motion can fulfill six single movements including head flexion, head extension, bending head left, bending head right, rotating head
left, and rotating head right. The instructions for each movement have two
programmable parameters: movement range and movement time. In other
words, the position and velocity of each movement can be defined. All nonconflicting multi-axis combined movements and sequences of movements
are able to be performed by the robotic system. This means that all complex
movements associated with a human neck can be conducted by the robotic
head/neck.
6.3 Inverse Kinematics and Statics Analysis
6.3.1 Neck Mechanism
A general configuration of the spring-based, cable-driven mechanism corresponding to Figure 6.2 is shown in Figure 6.4, in which Figures 6.4a–c show
the parallel mechanism of pitch and roll motions, general lateral bending of
the compressive spring, and yaw motion by the rotating pulley, respectively.
The yaw motion driven by two cables as shown in Figure 6.4c is straightforward; thus, we are mainly interested in analysis of the parallel mechanism
and compressive spring.
As shown in Figure 6.4a, a fixed coordinate frame OXYZ is attached to the
fixed plate, with the origin at the bottom center of the spring, and a body
frame oxyz is attached to the moving plate, with the origin at the top center of the spring. Four flexible cables with negligible mass and diameter are
connected to the moving platform at points B i (i = 1, 2, 3, 4) and pulled from
the base plate at point A i . Denote the force value along the cable as T i and
the cable length between two plates as l i . u i is the unit vector for the force
direction pointing to the base plate, thus T i u i =T i . The compressive spring
produces a force/torque between the fixed base and the moving platform to
support the robot head and facilitate the head motion. If the cables are actuated, the spring will bend in a plane formed by O, o, and o′, where o′ is the
vertical projection of o onto the fixed base. In this plane, a planar body frame
Oph is attached to this spring.
Development of a Low-Noise Bio-Inspired Humanoid Robot Neck
sealed in the sound insulation box, and (3) the drive system is dominated by
the low-friction and highly efficient cable-and-housing group, the humanoid
head/neck system can mimic well the motion of a human head without generating unacceptable motion noises.
6.2.3 Programming Head Movements
The 3-DOF neck motion can fulfill six single movements including head flexion, head extension, bending head left, bending head right, rotating head
left, and rotating head right. The instructions for each movement have two
programmable parameters: movement range and movement time. In other
words, the position and velocity of each movement can be defined. All nonconflicting multi-axis combined movements and sequences of movements
are able to be performed by the robotic system. This means that all complex
movements associated with a human neck can be conducted by the robotic
head/neck.
6.3 Inverse Kinematics and Statics Analysis
6.3.1 Neck Mechanism
A general configuration of the spring-based, cable-driven mechanism corresponding to Figure 6.2 is shown in Figure 6.4, in which Figures 6.4a–c show
the parallel mechanism of pitch and roll motions, general lateral bending of
the compressive spring, and yaw motion by the rotating pulley, respectively.
The yaw motion driven by two cables as shown in Figure 6.4c is straightforward; thus, we are mainly interested in analysis of the parallel mechanism
and compressive spring.
As shown in Figure 6.4a, a fixed coordinate frame OXYZ is attached to the
fixed plate, with the origin at the bottom center of the spring, and a body
frame oxyz is attached to the moving plate, with the origin at the top center of the spring. Four flexible cables with negligible mass and diameter are
connected to the moving platform at points B i (i = 1, 2, 3, 4) and pulled from
the base plate at point A i . Denote the force value along the cable as T i and
the cable length between two plates as l i . u i is the unit vector for the force
direction pointing to the base plate, thus T i u i =T i . The compressive spring
produces a force/torque between the fixed base and the moving platform to
support the robot head and facilitate the head motion. If the cables are actuated, the spring will bend in a plane formed by O, o, and o′, where o′ is the
vertical projection of o onto the fixed base. In this plane, a planar body frame
Oph is attached to this spring.