Twelve Degree of Freedom Baby Humanoid Head Using Shape Memory Alloy Actuators

Abstract

A biped mountable robotic baby head was developed using a combination of Biometal fiber and Flexinol shape memory alloy actuators (SMAs). SMAs were embedded in the skull and connected to the elastomeric skin at control points. An engineered architecture of the skull was fabricated, which incorporates all the SMA wires with 35 routine pulleys, two firewire complementary metal-oxide semiconductor cameras that serve as eyes, and a battery powered microcontroller base driving circuit with a total dimension of 140×90×110 mm3. The driving circuit was designed such that it can be easily integrated with a biped and allows programming in real-time. This 12DOF head was mounted on the body of a 21DOF miniature bipedal robot, resulting in a humanoid robot with a total of 33DOFs. Characterization results on the face and associated design issues are described, which provides a pathway for developing a humanlike facial anatomy using wire-based muscles. Numerical simulation based on SIMULINK was conducted to assess the performance of the prototypic robotic face, mainly focusing on the jaw movement. The nonlinear dynamics model along with governing equations for SMA actuators containing transcendental and switching functions was solved numerically and a generalized SIMULINK model was developed. Issues related to the integration of the robotic head with a biped are discussed using the kinematic model.

HBS-1: A Modular Child-Size 3D Printed Humanoid

“…This is due to the large overall form factor of the actuation technology. A detailed discussion of numerous actuation technologies has been given in our prior works [47][48][49][50]. In all of the robots described above, actuators are extremely important to determine the performance of the robot, and care must be taken in selecting both the actuation systems and motion transmission accessories.…”

“…Another proposal was an open platform DARwIn-OP based on a network-based modular structure and standard PC. The authors presented simulation software to study dynamic performance [50,64]. Other researchers proposed a design based on facial features in skeletal form.…”

“…The Mini Maestro 24-Channel USB Servo Controller is used to control the Power HD servos and Hitec Deluxe servos. A custom-made controlling circuit, whose operating principles and actuation sequences have been described by Tadesse et al [50], was adapted to actuate the fingers using shape memory alloy actuators. The circuit is based on a PIC 8-bit microcontroller (16F874) that provides a sequence to H-bridge amplifiers (L298), whose outputs are connected to each [22,32,35], as well.…”

“…The fuel cell systems have shown promise to power humanoid robots, as shown in [82]. SMAs have shown excellent results in humanoid development if the available space in the robot is a major concern; for instance, in the design of the head [50] and hands [74,83,84]. Therefore, SMAs are suitable candidates for finger actuation.…”

“…Future works include integrating flesh-like elastomeric skin on the face and artificial muscles that actuate control points. Investigating a biped mountable robotic head following the approach presented in our earlier work [47,50], the robotic head that has 12 DOF in the face could be integrated with HBS-1 to create a very high degree of freedom humanoid robot. Moreover, a new approach that was demonstrated in [91] will be employed to design and analyze a facially-expressive robot, to integrate it with HBS-1 and, hence, to create a full humanoid with facial expression capability, for use in many application areas, such as healthcare [92].…”