After a set of samples was produced, it was natural for them to be tested. Because they used his father's old work clothes, Chen Xin took advantage of the situation and invited his father to help him conduct the test.
However, Chen Xin's father was not satisfied with the exoskeleton protective suit made by Chen Xin.
"I can't walk or lift my hands. This is not suitable for work at all." Chen Xin's father put on this exoskeleton protective suit. After moving his body, he gave his opinion: "And this helmet is not suitable for work." It’s too big and very inconvenient.”
"Are there so many problems?" Chen Xin was a little surprised by his father's evaluation of the finished product.
Chen Xin's father wanted to take off the helmet on his head, but due to the joint structure of the exoskeleton, he could not bend his arm more than 90 degrees, so Chen Xin had to help take off the helmet.
Chen Xin's father took off the helmet and said to Chen Xin: "You need help from others to even take off the helmet. How can there be no problem with your design? The exoskeleton must at least ensure the normal activities of the human body and not cause any obstruction."
"Then let me adjust it. It should be a problem with the joint connection structure." Chen Xin listened to his father's suggestions humbly, and he himself had already seen the problems.
Because of cost concerns, Chen Xin adopted a relatively simple design for the exoskeleton's structure. However, it was obvious that this overly improvised design greatly reduced the exoskeleton's flexibility and could not even meet actual needs.
After helping his father remove the exoskeleton from his body, Chen Xin asked his father: "Dad, how about the protective clothing?"
"It's a bit heavy, but it's okay. It's almost like wearing a cotton-padded jacket." Chen Xin's father unzipped the protective suit and took it off: "It feels a little stuffy, but otherwise there's nothing wrong with it."
"That seems okay. I'll try to reduce some weight and adjust the breathability." Chen Xin took a pen and wrote down what his father said in a notebook beside him.
After taking off the slightly heavy protective exoskeleton suit, Chen Xin's father said to his son: "Problems with clothes are trivial matters. The key is this exoskeleton. This thing of yours is designed to do things for people." When wearing it, first of all, it cannot affect the flexibility of the body.
To design something, you must first figure out what you are designing it for. All your designs and functions should be designed around this core function. If your design deviates from this core function, then your design itself is wrong. Yes, no matter how good the design is, it is contrary to your original purpose.
So think about it carefully, what is the purpose of designing this thing, what do you want to do with it, what effect do you want to achieve, and whether your existing design is designed around this core. "
After saying this earnestly, Chen Xin's father patted his son on the shoulder, and was called by Chen Xin's mother to help.
After Chen Xin was taught by his father, he also readjusted his thinking and neatly placed the entire exoskeleton protective suit on the workbench, intending to readjust it.
One of the key points to summarize the problems mentioned by Chen Xin's father is that there are problems with the joint design of the exoskeleton.
Actions that are easy to achieve with human skeletal joints are not so easy to put on mechanical exoskeletons. The more flexible the mechanical joints are, the more complex their mechanisms are.
In order to reduce costs, Chen Xin uses swing connections to connect the exoskeleton joints, which can only swing to a certain extent in one plane. If he wants to move flexibly, he needs multiple joints to work together.
This undoubtedly limits the range of joint movement and flexibility of the exoskeleton.
It's okay to put it on the lower limbs. After all, human legs just do pendulum movements most of the time. They just need to swing back and forth. No one will do the horizontal split in a boring way.
But for the upper limbs, this design is a bit awkward.
The upper limbs of the human body, that is, the arms, in addition to the knuckles of the palms, also have four joints: shoulders, elbows, wrists, and radioulnar joints.
The shoulder joint has the functions of flexion, extension, abduction, and internal and external rotation. Therefore, the joint head is spherical and is called a ball joint. Taking advantage of the ball joint structure, the shoulder joint can flex 0°~180° and extend 0°. °~50°, abduction 0°~180°, internal and external rotation 0°~90°, it is one of the most flexible joints in the human body, even more flexible than the wrist joint.
Chen Xin's father said that the inability to lift his arms was largely due to the exoskeleton's movable joints on the shoulders.
After all, Chen Xin's shoulder joint of the exoskeleton is connected by two pendulums. One is responsible for swinging back and forth, and the other is responsible for swinging up and down. The cooperation of the two joints can also allow the arm to move flexibly within a certain range.
However, due to the limitations of the structure itself and the need to connect the assist structure, the flexibility of this part is limited.
The most obvious manifestation is that the user's arms cannot be raised higher than the shoulders, nor can they bend backwards.
In addition, the connecting joint of the exoskeleton elbow can only perform 0° to 90° of flexion and extension due to problems with the connection structure. Compared with the 0° to 150° of flexion and extension of the normal arm joint, it is a full 60° less. The range of movement makes it impossible for users to take off the helmet with their own hands.
If you want to improve flexibility, you can only adjust the connection structure of the exoskeleton joints to increase its angle of movement, or use a more complex structure to make it more flexible.
It is not impossible to use ball joints that have the same bone structure as the human body. It is just that there is a layer of cartilage on the connecting surfaces of the human bone joints. Only by relying on this layer of cartilage that can continuously regenerate can the human body withstand the wear and tear of the joints.
And even so, there are still people who suffer from severe joint wear and tear and joint strain due to high-intensity labor.
For machinery, if it is replaced with ball joints, mechanical wear will be an inevitable problem.
If they cannot be regenerated, they can only use bearings and lubrication to reduce friction, or replace them after serious wear. However, frequent replacement will undoubtedly increase maintenance costs, which goes against Chen Xin's original intention of reducing costs.
Moreover, using ordinary metal materials on ball joints cannot withstand high-intensity use, and using wear-resistant high-strength materials will increase costs.
In addition, the only way is to add more movable joints to achieve more flexible angles of movement, but the complex structure will make maintenance extremely troublesome, which put Chen Xin into an endless loop that made him bald.
