2016年8月28日星期日

The Report about hoverboard outage people falling down

First, the motor problem

1.A serious shortage of motor power

 Electric balance scooters is different than other forms of vehicles, motor power has two functions: (1) maintain the speed and acceleration; (2) to maintain the balance. The power required to maintain the balance is greater than the power required.
For example, the electric bicycle motor is only used to maintain speed, the motor lost power or power shortage is only unable to speed up or speed is not fast. And the electric self balancing scooter needs to maintain balance every hour, must have enough power margin to maintain a balance in the highest speed in case of an emergency, otherwise it will show the motor lost power lead to fall.

So, under normal circumstances, the electric bicycle 150W can guarantee a 80kg of people 15km/h speed, but the smart balance scooter needs more than 500W to ensure safety. If you want to maintain an instantaneous acceleration and deceleration, need for greater power.  At this stage, there are some serious shortage of motor power of some electric balance motor vehicles, and there is a serious shortage of power. And in order to cater to the user, the speed is too high, resulting in not enough power margin to maintain balance and throw the car. Therefore, we recommend production enterprises: according to the appropriate power of motor speed, increase the margin of power; (2) the maximum speed limit in the 20km / h, also according to different maximum velocities determined motor power.

2.The quality of motor Holzer
3.At present, most of the motors are brushless motors, and Holzer has become an important sensor for the control of the motor. Holzer's quality has become one of the important factors to determine the quality of electric balance scooter.

The main problems: the poor quality of the installation of Holzer; and Holzer wearing process. According to Holzer signal detecting abnormal, no parking security mechanism. The final performance of these problems, once the Holzer signal abnormal, the balance car on the fall. Even low speed or zero speed status will fall.

Therefore, we suggest that production enterprises: strictly control the supplier; the setting detection mechanism to detect the Hall state; 2-3 set emergency handling mechanism to make safe parking.

Second, controller problem

There are two kinds of problems in the design and production process of the controller. Problems existing in the design of controller and high current conditions, interference and leads to the disorder of a system; (2) in order to reduce the cost, choose the PCB manufacturer, production process exist large areas of rosin joint phenomenon.

1. Over current protection of a controller
In general, the controller will have over current protection, such as electric bicycle, when there is a large current output, the controller will reduce the output current, to protect the motor and controller. But for the smart self balancing scooter, current protection may cause body weak or motor disability, performance for the vehicle body can not to maintain the state of equilibrium, lead to the user directly fall. Recommendations: to do a good job in the protection and early warning mechanisms, rather than simply limit the current output.

2. Two MOS tube / fuse burned
In normal riding condition, the working current of the driving plate is in the normal range. When emergency acceleration and deceleration, and over the ridge, platform, etc., there will be a very large current impact, so the impact current if MOS tube or the fuse current exceeds the limit value, have burned the possibility of very large.
3. low power trigger under voltage protection
The output voltage of the battery, encountered large current will have a significant drop in, if the battery design range of normal working voltage is too low, encounter large current, battery voltage reduction may leads to a controller to trigger the undervoltage protection or power output abnormal, resulting in power of the body.
  4. controller process is poor and easy to wear.
In order to reduce costs, supplier quality can not be guaranteed, resulting in production process of rosin joint phenomenon, and production process quality inspection and outgoing quality detection are inadequate.

Third, the battery problem
1. Insufficient discharge performance of a battery
Electric scooter board in the actual use of the process may often encounter very large current, if the battery power shortage of the discharge performance is not enough, can not achieve a large current output, easily lead to a car crash. In addition, large current discharge if the battery voltage is low, weaken the discharge capacity of the battery, no obvious prompt and alarm, urgent user speeding, voltage will quickly pull low, power supply shortage, resulting in crash.
   2.  over current protection value of the battery is too low
In the case of rapid and sharp turns, the electric balance scooter battery discharge, if the battery is too low, it will lead to the car body in the process of cycling to trigger the battery over current protection.
3. battery under voltage protection value is too high
Under normal circumstances, the normal operating voltage of the controller should be higher than the discharge cut-off voltage of the battery. In the normal operating voltage range, the controller's voltage is lower than the discharge cut-off voltage of the battery, it will be very easy to trigger off the battery output, leading to the hoverboard power outages.

4. poor consistency of battery
During cycling, the battery appears over a single section, resulting in battery output off.

The last, the strength of the vehicle

Part of the overall structural design of the balance car is defective, resulting in the strength of the floor is very poor. Through bumpy road and over the stairs, leading to the floor break, a car broke.

Besides, others

There are many kinds of balancing scooter power outages. But the balancing scooter running and other means of transport is not the same. Because the balance car is a kind of system which has high stability requirements of system, requirement on overall product reliability is extremely high, any problem may have lead to imbalance in the balance system, therefore, the requirements of the whole system not only to in product design, production focus on quality, focusing on reliability, and requires the entire system provided enough detection mechanism, makes for products in the operation of any possible problems can be timely detected, and be able to make the product safe parking. This information comes from http://www.koowheel.com

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