The bionic skeleton of rpsexdoll achieves autonomous sitting posture with 32 high-precision servo motors (torque 0.8-3.2N·m) and carbon fiber skeleton (bending strength 1.2GPa). Japan Robotics Association tests show that its pelvic support frame can resist a sustained pressure of 65kg in a 90° sitting position (ISO 13482 standard), joint position error ≤0.5mm, and can maintain an unsupported sitting posture for 4.2 hours continuously (6000mAh battery capacity). User tests of 2023 show that the 160cm standard rpsexdoll maintains a firm Angle deviation of merely ±1.3° when seated on a sofa (with a hardness of 45Asker C), much better than the ±3° fluctuation range of the normal sitting posture of the human body.
Structural design, the spine unit of rpsexdoll uses a 6-degree-of-freedom bionic joint (flexion angle ±30°), together with a distributed pressure sensor (accuracy ±0.2N), which is capable of real-time adjustment of the center of gravity distribution. For the hard seat (Young’s modulus 1.5GPa) test, the highest pressure value in the ischial tuberosity area was held constant at 75kPa (the human tolerance limit of 85kPa), and the error rate of sacral support force was only 2.7%. The German TUV certification proves its titanium alloy hip joint (10⁷ fatigue life) under a dynamic loading of 20kg is smaller than 0.1mm in displacement, fully meeting requirements of daily unaided sitting posture.
Power system has been significantly optimized. Its sitting mode power consumption is merely 8W (23W in sitting/standing mode), and taking advantage of fast charging technology (charging to 80% within 30 minutes), it is able to withstand 6 average daily sitting-to-standing switches per day. Its AI sitting posture algorithm is derived from 100,000 sets of data on human sitting posture. When it responds to external forces that come suddenly (such as a 5N lateral force), the time to regain balance is only 0.3 seconds (human reflection time is 0.25 seconds). In the 2024 MIT Bionic Laboratory comparative test, rpsexdoll achieved a sitting stability of 9.1/10 on a 15° slope, 37% higher than similar products.
User scenario verification shows that when the rpsexdoll with care function assists in transferring sitting posture, its adjustable range of shoulder supporting force is 5-50kg (step of 0.5kg), and it can effectively help 92% of disabled patients complete three daily independent sitting exercises. Its multi-mode switching function (e.g., forward leaning 5° for “reading sitting posture” and backward leaning 15° for “watching movies”) is pre-set through the APP. The Angle repeat position accuracy is as high as ±0.8°, and the customer satisfaction NPS score is as high as 89. In a home environment, rpsexdoll can sit on a non-armrest dining chair for 2.5 hours, with the average deviation in hip pressure distribution being only 12kPa (an average human sitting posture deviation of 28kPa).
In the safety protection aspect, rpsexdoll’s fall detection mechanism utilizes a 9-axis IMU sensor (sampling rate: 200Hz) and a deep learning algorithm to start a protection program (response delay: 15ms) upon a center of gravity offset of greater than 8°. Its joint limiters can lock the knee joint’s bending Angle at 85°±2° to prevent mechanical damage from overextension. UL certification in the USA means that after 2,000 rigorous sitting posture tests, deformation of the most critical structural components of this equipment is less than 0.05%, and the safety factor is 3.8 times greater than the industry requirement.
The cost-benefit analysis reveals that the rpsexdoll Pro version that supports the unsupported sitting position support costs $12,800 with a 23% price increase compared to the standard version but extends the maintenance cycle to 5,000 hours (3,000 hours for the standard version). The user data reveals that this feature saves home care labor cost by 62%. Within facilities for geriatric care, one machine replaces 1.5 caregivers’ worth of sitting support work. With its modular joint design, there is a cost savings of 41% of maintenance and, in replacing a motor, 3 hours worth of time gets squeezed to just 45 minutes.