Human civilization relies heavily on the ability to precisely process liquids. Switching between liquid capture and release plays a fundamental role in the handling of various liquids, with applications that demand reversible, spatially and temporally precise, volumetrically accurate and programmable control over the liquid, independent of the details of the employed solid tools and processed liquids. However, current fluidic techniques do not fully meet these requirements. Here we present connected polyhedral frames to effectively address this challenge by tailoring liquid continuity between frames to dictate the liquid capture or release of individual frames, with an overall network that is readily switchable locally, dynamically and reversibly. Each frame captures or releases liquids, independent of its base materials, structures and processed liquids. The connected polyhedral frames are a versatile tool that enables many important functions including three-dimensional (3D) programmable patterning of liquids, 3D spatiotemporal control of concentrations of multiple materials, packaging of 3D liquid arrays and large-scale manipulation of multiple liquids, thus considerably advancing many fields, including interface science and soft materials.

It is necessary to upgrade and transform the sorting equipment in the industrial production line. In order to improve production efficiency and reduce labor intensity, a high-speed lightweight parallel mechanism control system for the high-speed sorting and packaging of light items was studied. A fuzzy PID controller based on genetic algorithm (GA) optimization is proposed according to the nonlinear and strong coupling characteristics of the parallel mechanism (PM) control system. The inverse kinematic analysis was conducted to map the workspace trajectory tracking problem to the joint space. It was transformed into the trajectory planning and solving problems in the joint space. The motion trajectory was obtained utilizing quintic polynomial interpolation. Finally, the servo control system model was established, and the PID control parameters were optimized and self-tuned by the GA. They were applied to the fuzzy PID controller for simulation experiments. The simulation results showed that the GA-optimized fuzzy PID control system compared with the fuzzy PID control system had a 23.39% shorter rise time, 22.32% less regulation time, and 7.18% less steady-state error. The control system had a good dynamic and steady-state performance.

Three translational (3T) degree-of-freedom (DOF) parallel mechanism is widely used in the industrial field because of its compact structure and excellent dynamic performance. Combined with the 3T parallel mechanism studied at this stage, a novel 3T parallel mechanism is proposed. Firstly, the DOF of the mechanism is analyzed by using the screw theory. Secondly, the position, velocity, and singularity of the mechanism are analyzed, and the workspace of the mechanism is analyzed through the positive position solution. Then, the trajectory planning in joint space and coordinate space is completed, and a common mathematical model of grasping trajectory is established. Thirdly, the kinematics simulation analysis of the mechanism is carried out. Finally, the prototype platform was built and the grasping experiment was carried out, which verified the rationality of the mechanism design and the correctness of the theoretical analysis.

A novel synchronous telescopic parallelogram mechanism with movement realized by a belt drive is proposed, from which a compound kinematic limb is derived. According to the configuration derivation, a class of two-translation (2T), three-translation (3T) and three-translation-one-rotation (3T1R) parallel mechanisms is obtained by assembling the above kinematic limbs. Since the motion of these limbs in the parallelogram mechanism are dependent, screw theory is applied to illustrate the mobility of the obtained lower mobility parallel mechanisms. Moreover, through the simplified kinematic equations for these mechanisms, their position, velocity and singularity are analyzed and their workspaces are calculated. Finally, the prototype of the 2T parallel mechanism is manufactured and experimented to validate mobility and motion feasibility.