Home Appliance ASCII Hitachi's Evonomy Little Robot Vacuum Cleaner "Minimal" Secret Story

Hitachi's first robot vacuum cleaner is a lump of unique technology.If there is a manufacturer who wants to make such a thing other than Hitachi, there is a commitment that you want to see.

"Minimaru RV-DX1 (Minimal)" is the first robot vacuum cleaner that Hitachi Appliance announced in 2003.25cm wide x height 9.It is a compact size of 2cm and makes a small turn, and it cleans well in a narrow Japanese house.There is also a function to automatically avoid furniture legs.It was released on November 19, last year at around 100,000 yen.

A gorgeously appointed storm full member as a focus product.The making video shows a minimalist who moves with a small body, "Oh!"

The men who gathered for the development team were men who have created a vacuum cleaner in Hitachi.The biggest goal is to make it smaller but powerful.If the performance as a vacuum cleaner decreases due to the compact, it will fall.I am confident in the suction power of the vacuum cleaner that has been making since 1955.The "Hitachi vacuum cleaner" brand cannot be damaged.

Hitachi announced a prototype of a robot vacuum cleaner in 2003, 13 years ago.Going back to history, the development of robot vacuum cleaners itself has been promoted since 1983.We visited the Hitachi Appliance Taga Office, a manufacturing base, to see what kind of path was before the minimal release.

■ The developers who told me the story ──Yasuhiro Matsui: Mr. Norikazu Ito, the chief researcher in charge of running control at the research institute: Yusuke Yabuki, the chief engineer of minimalism: Ryo Yamaya in charge of the engineer, the layout of the main body.Mr. Naoki Kato in charge of the bumper and the detailed design related to wheels: Mr. Takuya Tachibana, such as the side brush, charging stand, instruction manual, etc.: Dust case, garbage press mechanism, etc.

Fight with "6cm"

The biggest feature of minimimals is a small size of 25cm wide.In fact, this has not changed from the prototype announced 13 years ago.The average furniture size concluded that "25cm wide would increase the probability of getting into the tables and chair legs."There are many narrow gaps in a small Japanese house in Japan, so if the size is large, you will not be able to clean satisfactory.What is particularly difficult is the corner of the room.The prototype 13 years ago had already had a mechanism for cleaning corners.Yasuhiro Matsui, who was in charge of minimal driving control, says.

"At that time, when a robot vacuum cleaner had just begun to appear, Hitachi said," Because the name of a vacuum cleaner is attached, the sucking port is quite solid. From that time, the robot cleaning was made.There were many rounds, but the corner of the room could not be cleaned in the circle, so when I passed through the corner of the room, I was making a mechanical prototype in which the suction port slides and jumps out. "

The prototype was well made, but it was not released after all.The reason is performance and marketability.Even if it can be made as a robot vacuum cleaner, it has not been satisfied as a vacuum cleaner.The market was still small.If the production volume decreases, the unit price will be extremely expensive at several hundred thousand yen.Basic research has been performed, but in terms of performance and business, development has been paused for four years since 2008.

The project resumed in 2012.It was the time when the robot vacuum cleaner market that I robot pioneered in "Rumba" has expanded, and it has become an unprecedented entire vacuum cleaner.I don't know if Hitachi will be able to launch a satisfactory product, but at least we can't compete unless we continue to develop.The battle with the robot vacuum cleaner has begun again.

The biggest difficulty was to cut "6cm".

A prototype 13 years ago and a minimal, the most different point is.At that time, the height was 13cm, which was nearly 4cm higher than it is now.Unless the height was reduced, the development team first expanded the width to 34 cm and instead prototyped a flat model with a lower height.It is almost the size of a rumba, but is about 1cm small.In addition, the width of the parts is 31cm by devising the arrangement of parts and mechanisms.The conclusion was that 31cm was the limit to shorten the size in a normal way.

■ Prototype size (width) Width 340 x 92mm high (2012) Width 310 x height 92mm (2014) Width 250 x 92mm high (2016)

But what is required is 25cm wide.There is no point in reducing 6cm from 31cm.The team members were worried and came to a conclusion.Develop all element parts from scratch for minimalism.Engineer Yusuke Yabuki says.

"In order to make it smaller, I had to reconsider everything from the previous layout to each component, and I had to incorporate a structure that other companies did not handle.

Make suspension and gear from zero

The battle with 6cm began in the "suction port" where the garbage was sucked.

Initially, the suction port was on the main body or between wheels.However, when the width of the main unit is narrowed, the width of the wheels cannot be entered.The size of the suction port cannot be changed because the suction port is small and the dust is reduced.The fan motor was forced to shift the suction port behind the main unit, and instead brought it to a rarity instead.

The minimal fan motor is a small high-power fan motor R, which was newly developed according to the characteristics required for robot vacuum cleaners based on the company's stick vacuum cleaner "PV-BC500".It was efficient and highly gathered performance was expected even for small electricity.The size of this motor is reduced to a diameter of 66 mm or less, but it still does not hit the wheel unit in the 25cm wide body.The troubled team thought about minimizing the suspension and gears that make up wheel units.

The seesaw -style suspension usually used in the wheels of the robot vacuum cleaner requires a space for securing the axis and a large space to secure the upper and lower strokes.In order to think about the mechanism to solve this, we first prototyped a simple mechanism that the spring moves up and down.However, just being pushed from the side, the movement fluctuates and does not work well.Then I also created a suspension of a binocaite mechanism that moves with an arm.This time, he ran a straight course well, but it was still tough to try it assuming a complex driving environment at home.

After worrying, I adopted the "Strut Suspension" used for cars.The wheels move up and down, so they can be installed in a small space, but this is the first time to be installed in a robot vacuum cleaner.Normally, the strut -type suspension is made of metal, but due to the weight, cost and productivity, it is necessary to replace it with resin.It was said that it was very difficult to change the material and simplify the structure, but to use it as a suspension.

At the same time as the suspension, the gear method used for the deceleration mechanism was considered.In normal flat gears, we researched whether other methods could be used because they needed to be lengthed side by side.The first leading candidate was "Mysterious Planning Gear".A combination of two types of gears with different teeth on one axis, and placed inside and outside.In the calculation, I thought it could be good, but when I moved it, the driving noise of the gear was unusually noisy.The efficiency as a gear was poor.

The size and inefficient of noise are caused by gear interference.Therefore, I tried the "cycloid gear" mechanism that I tried to reduce interference.Gears inside the wheels do not require as long as flat gears.The gears are constant, the loss due to friction is low, and the gear with a high deceleration ratio can be smaller and lighter.When I tried it, it worked.However, the mass production design was more difficult than expected.

Like a strut -type suspension, it is the first time to use a cycloid gear for robot vacuum cleaners.Even if the prototype can be done well, if you try to mass production, the gear will not turn around due to a slight size.The developer said that he had returned the gears many times between the office and the gear factory, repeating detailed adjustments, and took a long time.

"It was hard to create a new mechanism because I had never done anywhere and had no track record. Prototypes can be done in about a month, but it took about six months to get the accuracy of mass production.Te. The suspension was the first structure, so if you did a life test, it would be gone even on the way. "(Yusuke Yabuki)

Gear and suspension were talking to reporters at the product presentation, but the story is not over yet.Other element parts were also unique to small size.

For example, a gear used in the "side brush" that stirs garbage in the corner of the room.Again, we stopped flat gears to reduce the size, and changed to a two -step deceleration system that combines two small "warm gears".The "rotating brush", which also stirs garbage, has been changed to a two -speed reduction mechanism using two timing belts.The first -stage deceleration mechanism was installed right beside the dust, so that the body was as much as possible.

The motor of the rotating brush itself was also re -created.The motor needed to be smaller due to the size down, but it would not make sense if the brush could not be maintained.Therefore, by re -analyzing the magnet of the motor, it has developed a motor that can ensure sufficient rotation and torque in the brush operation.

The board is located up and down two layers, sewing the gaps and placing parts

It seems that the design of the control substrate was also difficult.

The substrate must be installed in order to reduce the height of the main unit in avoiding the frustrating fan motor, and becomes a shape that is not an unpleasant shape.However, the engineer on the board disliked the U -shaped shape, saying, "It is inefficient to draw patterns."That is not all.In addition to the normal control circuit, there was also a problem that a circuit for the operation panel with a driving button etc. had to be attached.

After the worries, the development side proposed the idea that "we will create a space where we can put two -layer boards."With the idea of "making the board up and down two floors", the engineer on the board was surprised to hear Do Ha.He said that he put two layers of boards on the drawing drawn with a 3D CAD, and placed parts for the board on the substrate to build a "building".

"You can have a" building "(part for the board) built here, and you will have it here for the vacant land, and you will have it here.We decided to get a place to put in reinforcements. "

The "dust case" on the suction port is also devised.We decided to add a "back valve" structure so that the garbage that comes in with the airflow from below does not spill.

The reverse valve was originally used in the conventional vacuum cleaner, but in the same structure as before, the ability of the enhanced fan motor will be lost in order to raise the rubber valve.So we developed a rotating lid.It is a mechanism that automatically opens and closes with the power of the dust case, and this is also a unique development only for this time.

The biggest problem in the dust case is that it is small and has a small capacity that can suck garbage.

To solve it, I first put a wing -like rib in the case.Until then, the test garbage, which had been staying near the entrance, has become smoothly flowing through the case, and more garbage can be hesitated.However, I still twist my head because the capacity is still not enough, and I think about "press driving" that compresses garbage.There is no way to use it for compression because it has a strong motor.However, if you always drive with the maximum output during cleaning, the driving time will be insufficient and the driving sound will increase.When he returned to the charging table, he decided to devise a "garbage press" function that drives the garbage to compress the garbage.

Running technology that chose a road that is the opposite of Rumba

Driving technology is also unique to small size."Minimaru AI".

In the robot vacuum cleaner market, a robot vacuum cleaner that tries to finish cleaning in the shortest distance using the "SLAM" technology that runs while creating a map of the home.However, minimal chose the old -fashioned "random driving", which dares a long mileage.The reason was that the mapping was still left behind.I wanted to improve the performance by expanding the range that can be cleaned even if it is small.

"If you map it, you can do a place that can only go once, but once it is, the garbage cannot be removed. For example, the flooring accumulates garbage in the groove. It should be moved in parallel in the groove, but when it does not work.There is. If it is the current technology, it is not possible to determine that I missed the trash. I judge that it is better to have a random driving clean as much as possible during driving. "(Yasuhiro Matsui).

The driving speed was the place to stick to instead of mapping.Movement such as driving speed, direction change, etc. quickly moves.For example, when changing directions, there is a flow of "deceleration → rotation → acceleration".In a general robot vacuum cleaner, waiting time occurs when you move to the next movement, but minimal curves almost without waiting time.

"There is a surprising time for a general robot vacuum cleaner where the main body is not moving. In fact, when I tried to analyze the histogram, the same ratio is the time near zero and the maximum speed.It was distributed. I thought that such a waste of time had to be reduced as much as possible. "

That said, I didn't completely ignore the mapping technology.In fact, at the beginning of the development, he also made a prototype using mapping technology, but as a result of improving the performance as a vacuum cleaner, he finally settled on random driving.Competition i robots have been running randomly, but the Rumba "980" series has adopted a mapping method "VSLAM" using a camera.Minimal and Rumba chose the opposite evolution.

"I think that if I can find the advantages of mapping in the future of technology, I will shift there, but the current answer will move and smoke. There will be a revolutionary function to discover garbage in the future.I would like to think if possible. "(Mr. Norikazu Ito)

"Hitachi of Technology", not "Arashi no HITACHI"

The interview that the developers spoke with a lot of enthusiasm exceeded the scheduled time and exceeded three hours.It was impressive that most of the time was spent on gear and suspension structures, and I felt like I had visited engineering seminars.

The characteristic of the minimal is the original idea of "roboting a vacuum cleaner."It is exactly the opposite of thinking that an Irobot would convert a mine removal robot into a vacuum cleaner.How do you robot a vacuum cleaner?It doesn't make sense if you can't clean a narrow house in Japan, so let's reduce the size.If the element parts are small and the cleaning capacity is reduced, there is no point, and if the size of the parts related to cleaning can be considered, the internal structure should be considered so that it can be inserted without changing it.It is fashionable to use mapping technology to clean it efficiently, but if you think about cleansing the room, it is better to move quickly.

Hitachi was the last in the industry as a robot vacuum cleaner, but when I heard the development episode, I felt that I was able to reconsider the robot vacuum cleaner from scratch.There is a passion that is different from a new product that has just changed the concept.When I thought again, this was Hitachi.It looks like a soft image in the storm commercial, but if you skin up, you'll get a lumpy.The Japanese -style engineer group with great confidence in technical and performance was a company called Hitachi.I thought so while looking up at the huge nuclear turbine installed in front of Hitachi Station with the lack of sugar.

Born in 1983, Kazimen is a hobby of housework.I plan to evolve into my dad this year.We are looking for from Facebook.

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