A multi-fingered hand that can grasp and manipulate a variety of objects is an option for assisting people in their daily lives. However, the range of torque output that can be handled by the multi-fingered hand is very limited compared to the capability of the human hand. In this paper, we introduce a new multi-fingered hand consisting of a dynamic pulley and a linkage mechanism, aiming to achieve a human-like output torque with a human-like size. The proposed multi-fingered hand can achieve a fingertip force of 50N, which is equivalent to that of a human, and at the same time can perform delicate operations such as picking up a coin on a desk. In addition, we realized the stay-on-tab opening task of a can by utilizing fingertip strength.

Many control methods have been studied on the assumption that the feet of biped robots contact the ground with four points. However, it is difficult for almost all of such biped robots to maintain four-point contact on uneven terrains because they have rigid and flat soles. In order to solve the problem, foot mechanisms should be studied. In 2003, we developed WS-1R (Waseda Shoes - No.1 Refined) which is able to maintain four-point contact. However, it is difficult to deal with the concave or convex ground because of the problems of the contact detection and sideways slip. So, WS-5 (Waseda Shoes - No.5) has been developed. To avoid the slip of the foot, a cam-slider locking system consisting of a solenoid and a cam is constructed and installed at the foot. Also, linear encoders are employed to measure the position of the foot sliders. Through walking experiments on uneven terrains, the effectiveness of WS-5 is confirmed.

Previously, the realization of ascending and descending stairs and landing pattern modification control by WL-16RII were reported. However, it is difficult to use the landing pattern modification control when ascending stairs, because of the insufficient stroke of linear actuators. In this report, the design of a double stage linear actuator with a larger expansion and contraction ratio is described. The new linear actuators developed have been installed in WL-16RII, and several experiments were conducted. Through experiments involving walking with a wide step length and ascending a stair with landing pattern modification control, the effectiveness of the actuator developed is confirmed.

This paper describes how to compensate unknown external forces caused by a rider's motion of a biped walking vehicle. When external forces act on a robot's waist, the waist is accelerated so that a measured ZMP may be equal to a reference ZMP. To inhibit the divergence of the waist motion, the reference ZMP is varied inside a support polygon. However, if a large external force acts on a robot, the waist trajectory does not converge by only controlling a reference ZMP. So, ZMP trajectory is varied by changing a foot-landing point. Using the proposed control method, WL-16RIV (Waseda Leg-No. 16 Refined IV) achieved a stable human-carrying walking under unknown external forces which exert forward and sideways on the robot's waist. Through various walking experiments, the effectiveness of the proposed method was confirmed.

Many researchers have been studied on acceleration control algorithms for biped robots to deal with uneven terrain. However, the control algorithms are difficult to be used for human-carrying biped walking robots because of modeling errors. In this paper, a landing pattern modification method is proposed which based on nonlinear compliance control. Theoretical compliance displacements calculated from a walking pattern are compared with the actual compliance displacements, while a robot's foot touches slightly uneven terrain. In result, the height of landing terrain is detected, and the preset walking pattern is modified. Using this method, a human-carrying biped robot would be able to walk stably on uneven terrain. This pattern modification method does not need any special sensors except force sensors. Through various walking experiments, the effectiveness of the method is confirmed

This paper describes one method to stop suddenly and safely avoid falling using only hardware and without a computer system. This method consists of attaching a braking function to leg actuators and the development of a fall avoidance mechanism, attached to the robot's foot. Using the human-carrying biped locomotor WL-16RII developed by Sugahara et al., the effectiveness of the method proposed in this paper was confirmed through an emergency stopping experiment during walking, while carrying a heavy load

Many researchers have been studying on walking control methods for biped robots. However, the effectiveness of these control methods was not verified in outdoor environments such as pedestrian roads and gravel roads. In this paper, a landing pattern modification method adaptable to uneven terrain in a real environment is proposed which is based on a predictive attitude compensation control and a nonlinear compliance control. This method does not require any other sensors except force sensors. Also, a new biped foot system is described which can form larger support polygons on uneven terrain than conventional biped foot systems. Using the modification method and the foot system, WL-16RII (Waseda Leg-No.16 Refined II) achieved a stable walk on bumpy terrain with 20 mm height and 10 degrees inclination. Furthermore, a stable dynamic walk was realized on a paved road, when a human rode it. Through various walking experiments, the effectiveness of the method was confirmed

This paper describes a passive dynamic model of passenger for a biped walking vehicle. The walking pattern generation that enables stable walking even if passenger sits naturally is also described. The model consists of lower-limbs part assumed to be fixed to the robot, and the upper body assumed to be 1 particle with 2 DOF mounted on the seat via 2 springs and dampers. The parameters are identified through waist shaking experiments by using a force-torque sensor under the seat. The walking pattern generation method involves the proposed model being built onto a strict model of the robot, and through iteration computation, a stable walking pattern is generated. The effectiveness of the proposed method is confirmed through experiments

This paper describes the means of tuning-up method of the walking parameters to go up and down stairs for a biped robot with leg mechanisms using Stewart platforms. It has been confirmed that the stroke range of use could be reduced by tuning up the waist yaw trajectory and preset ZMP trajectories for motion pattern generation. By using the developed method, a walking experiment involving movement up and down a stair with the rise of 250 mm and certain walking experiments ascending and descending stairs carrying a human were successfully completed. Through these experiments, the effectiveness of the proposed method was confirmed.